# My comprehensive review of the Aqua Terra and my personal notes on the 8500



## CitizenM

Generally, I write reviews on obscure, esoteric watches because you basically can't see them in person, at least not in America, and there's not much information about them out there. But the Omega AT8500 is different. It's a universally well-loved watch with dozens of reviews and magazine articles. So I wondered, having read many of those reviews, what I could possibly add that would be of help to people who are interested in buying one.










Well, I decided that I should focus on details that I think are often overlooked, aesthetically speaking, as well as provide easy access to technical information on the 8500 inside. Finally, I, in cooperation with my colleague and former roommate, and all around hardcore Omega collector, performed some simple testing on three 8500 movements (all of the non-SI14 variety) and I'll share our experiences.

The Aqua Terra is often considered to be the ultimate all around luxury watch. Stylistically, it's a sports watch that doesn't go overboard. The styling is interesting and unique without being aggressive. The size is also right, mine being 39mm. It appears slightly small on my wrist, but in my opinion, at least since I wear watches in a professional environment, better a little small than a little big, and its light weight is a refreshing comfort after my heavy 46mm Ananta, or my old 2500C PO. Basically, it strikes that idea balance. It's not too thick, not too large, and is interesting without being flashy. 










And it's "all star" nature doesn't stop at good looks. Unique in its class, it has a 150m water resistance rating and, slightly less uniquely, a screw down crown. Normally I don't like screw down crowns. They're inherently more fragile designs insofar as you can strip the thread, and are a pain to work with as a watch collector because you can't hand wind the watch easily. But since Omega is giving me a nice, usable 150m rating, I think it's a worthy tradeoff since I might actually dare to take this skin diving.










And perhaps at this point it should go without saying, but it has a world class 8500 calibre. More on that later.

*Aesthetics*

I chose the gray model over the silver or black model because I thought it was the right balance between contrast with the hands/indices/lume while not obscuring the cool "teak" lines. The black model makes it a little difficult to see the lines, but the silver model somewhat hides the beautiful hands and lume. Did I make the right decision? I don't really know. Personally, I love the silver model too and I would probably be just as happy with it. I don't like the Golf model, because the green looks a bit tacky to me, but that's just my opinion and I haven't seen that one in person. I personally think they're all winners, stylistically, and I like both sizes too. I wanted a reprieve from my giant heavy Seiko, so I want small. I don't know if that was the right call for me personally, but I'm satisfied with the size at least, and it is very light.










One of the nice touches on these watches that people don't bring up often is that the hands, indices and movement are white gold/rhodium plated, giving a really beautiful "white" shiny finish to them. I've never been a fan of white gold before this watch. For one, it was difficult for me to appreciate when it wasn't right next to well polished stainless steel and two, it's relatively fragile in terms of wear. But since this watch has a steel case, the white gold is very obvious and looks extremely "pure." Furthermore, since there's no way for me to scuff the hands or what have you, the wear concerns are not important. So I'm very pleased with the white gold on this one and it's very well executed.










Another thing I've not seen mentioned is how tall the indices are. The dial is quite flat, despite the teak lines, but the tall indices provide some depth to the thing, which looks great at sharp angles.



















I also really like the date window. One of the things I didn't like about the Planet Ocean was that it was a very simple cut out to the date ring, and it looked a bit rushed in my view. Here, the angular border to the date matches the basic shape of the indices and adds a little balance to the look.










By the way, the actual numbers on the date ring are in a metallic/silver paint, which is a nice touch. It's very difficult to take a photo where they don't look white though, so you're just going to have to trust me.



















Additionally, the fine polishing of the white gold throughout the watch have a cool prism effect at certain angles, given off beautiful colors. Now, the master of this technique, so far as I'm aware, is Seiko, and my Ananta actually executes this much better. However, it may be a byproduct of using white gold instead of steel that made it more difficult, or maybe Omega consciously chose to make this effect somewhat subdued. Either way, in the right lighting, it's quite beautiful.








Note the prism on the minute hand.

For comparison of Seiko's version, check out the 12:00 mark on my Ananta:









The lume is nice. I definitely prefer blue to green lume, and it was a big bonus to me. For one, I like the color blue, but more important, it appears to me that blue lume is more "white" during the day time than green lume. The lume is fairly liberally applied to the indices, and at certain angles, the bright white (not visibly glowing) lume conrasts sharply and beautiful with the dark gray dial. 










That said, the lume is inadequate in terms of utility. Frankly speaking, Omega chose to go an artistic route in applying it to the hands. That is, it's only in a thin line on the hour hand, and at the very tip of the minutes and seconds hands. This causes more problems than simply not lasting very long. Namely, at night, it's very difficult to tell the seconds and minutes hand apart at a glance. You have to look at it for a couple seconds so you can see which one's moving, then you can isolate the other. The other issue is that either the seconds or minutes hand easily and completely obscures the thin strip of lume on the hour hand. This happens in all watches to some degree, but because there is so little light given off in the first place, it seems more problematic here. Finally, there just isn't enough lume. It's very well (evenly) applied, but don't expect this to last for hours. In my opinion, the blue lume here was chosen for aesthetic purposes and not practical ones. That said, it succeeds aesthetically, so I think it has paid off overall.

The crystal has a nice subtle curvature to it and is curved on both sides. An easy way to tell most cheaper watches from most nicer watches, if they have domed crystals, is to look into the crystal at an extreme lateral angle. Cheaper crystals are usually not curved on the inside, so the thickness of the crystal effectively increases quite a bit. As a result, there is a lot of distortion and cloudiness at those angles. As you might expect, the AT does not experience this.









Note that you can still see clearly even at this extreme angle. 








Note the curvature.











The AT also has some excellent anti-reflective coating on it. Unlike prior incarnations, this one does not give off the blue hue. It is the second best I've ever seen, behind Citizen's propriety AR, which simply makes the crystal invisible. 








This photo was taken in sunlight, but there is no obvious glare.

Now, onto my two favorite stylistic things about the AT8500: the hands and the movement decoration. There's not a lot to say here that the pictures don't already. I just love the cool hand shapes and the movement decoration is some of the finest I've ever seen. In fact, barring skeletonized movements, this is probably my favorite looking non-exotic movement out there (i.e. barring Breguet, Vacheron, A. Lange and so on). But the photos speak for themselves, so there isn't much to talk about here.










The bracelet, like most from Omega, is very well made. It's extremely comfortable, probably the most comfortable I've ever worn, behind my old PO. It also uses the superior (in my opinion) screw type construction that's both easier to work with and less likely to fail. That said, the bracelet is very plain and doesn't warrant much discussion. It's as if Omega sat down and thought "let's make a very well crafted generic watch bracelet." Furthermore, it has a fully brushed design, excepting the very sides of the links, which I like in part because it's so easy to refinish. But it doesn't match the overall polished top of the watch case. The lugs are brushed to match the bracelet (I guess), but the brushing is in a different angle than the bracelet, and frankly, the finish appears a bit amateurish on the lugs. Personally, I don't think the bracelet matches the case in terms of polishing very well. There is a safety built in with a part of the clasp being held in by little ball bearings, which do not appear to be metallic and are perhaps ceramic for wear reduction. It's a nice safety feature, and if the clasp comes undone, it will not fall of your wrist. 








Note the polishing on the case near the bracelet and the bracelet itself.




















*Movement
*








Now, if you're part of the emerging trend of people who believe that stock ETA movements are as good as movements are ever going to get, just skip this section and you probably ought to skip the watch.


Good, now that we're alone, let me give a little overview of what makes the 8500 special, its strengths, weaknesses and my data points. 

Before I get to the substantive technical movement stuff, I wanted to mention a couple of interesting things about this movement. First off, like so-called "true GMT" watches, it has a fully independente 12 hour hand, which makes setting it a breeze since you don't have to hack the seconds to change time zones or for daylight savings time. Like almost all other watches with an independent 12 hour hand, however, it eliminates the quickset date. Nonetheless, it takes extremely little effort to change the date. Like most GMTs, this can also set the date backwards. This would be unremarkable, except that it's not a GMT movement. Indeed, it wasn't even built around being GMT, and we're only just now getting to a GMT version of the calibre with a second time zone.

The second slightly interesting thing I'd like to mention is just how smooth the winding is. Like its 2500 predecessors, winding this watch is totally smooth, to the point that you wonder if you're actually winding or just spinning the crown. It's totally silent and you can feel absolutely no ratcheting. I had to look into the movement and watch the barrels turn to confirm it wasn't broken. I don't know if there's any benefit to this design, but it's interesting and feels very high quality. 

The co-axial escapement has been discussed at extreme length for years, and I don't want to spend too much time on it here since it has been so thoroughly covered. Essentially, the promise of the co-ax is that because of reduced friction in the escapement, there is less wear and tear, less (or no) need for lubrication on the escapement, and ultimately, as a byproduct, greater stability. Does it achieve those goals? Well, beats me, but it sure sounds cool. I guess we'll find out in 20 years.











I actually think the most interesting part of the 8500 was the choice to go with a double barrel mainspring. That, by itself, is not all that rare. Many watches that feature an extreme power reserve use double barrel mainsprings to achieve it. Yet Omega only obtained a very good power reserve, hardly an amazing one. One of its primary competitors, the Grand Seiko, gets 72 hours on just one spring. So why two springs? 
Well, the design is apparently to try to make the release of energy more constant throughout the various states of wind. So far as my research suggests, only one mainspring is unwinding at 100%, and the second one starts releasing energy into the movement when the first one has a certain drop in output, stabilizing the output as a result. The consequence of having them not work at the same time all the time is, ultimately, a shorter power reserve than could otherwise have been achieved. On the other hand, the more constant power flow should help maintain accuracy even at low levels of power reserve. An interesting side note is that the barrels are both DLC coated, apparently for wear resistance. Whatever the case, the black barrels do look cool peaking out of the very edge of the 8500. 










Another interesting part of this movement that hasn't been talked about is that the rotor is floated on unique zirconium oxide bearings. Apparently, Omega wanted the rotor to be nearly frictionless, extraordinarily quiet and for the user not to be able to feel it moving. I lack the chemistry/physics pedigree to tell you if these things actually work, but I can tell you that the rotor is totally silent and I can't feel it all. Now, I'm not sure why that required special technology to accomplish. After I, I can't feel the Ananta's rotor moving. I think this is true of most bidirectional winding mechanisms. But perhaps these bearings will increase wear resistance over time. 

The 8500s also feature special beryllium-free balance wheels. Supposedly this material is more resistant to differences in temperature. Interestingly, the only other maker that uses similar balance wheels is Breguet.










The balance, like the older 2500, is free sprung and adjusted by screws on the inside of the balance. Free sprung versus regulated balances is another issue that is debated among watch enthusiasts, although it seems like most of the high-end watch makers have come down in favor of free sprung balances. Rolex, JLC, Patek and Omega are just a few examples of companies using free sprung balances. There are a few high end Swiss and German makers left that still use regulated balances, but the most notably proponent of them is Seiko, which uses regulated balances in their entire range, from a $70 Seiko 5 to a $50,000 Credor. There are a number of arguments in favor of each that we needn't go into here. Suffice to say that one maker of the most accurate watches in the world, Seiko, uses one, and the maker of the other most accurate mechanical watches in the world, Patek, uses the other. Omega has clearly taken the position in favor of free sprung balances and used them almost exclusively for over a decade now. Personally, I think I come down in favor of free sprung balances too, but either, if well made, can be excellent.










The 8500 also features two different hairsprings, depending on the model of watch.

In mine, and most others, it uses an anachron hairspring. I have no idea what the benefits of an anachron hairspring are and it seems extremely hard to find much data about. Far better publicized is the SI-14 hairspring, which is available only on the lady's (smaller) version of the 8500, all annual calendar models, the Planet Ocean and a miscellaneous few others. At any rate, the anachron hairspring is apparently the top of Swatch Group's hairsprings, aside from the new SI-14. How does it compare to Nivarox-1 hairspring available in top & chronometer grade ETA calibres? Beats me. Is it another word for Nivarox-1? Well, I can't say. The very few sources of information on it have suggested that it's some mysterious grade higher than Nivarox-1. Unfortunately, Omega has simply decided not to espouse the virtues of whatever material it uses in the non SI-14 models, so I can't be of much help here. What we do know is that it's probably among the highest quality ordinary material hairsprings available. 








Note the suspiciously blank area on the caseback where SI-14 is written on the Planet Ocean. It's almost as if they were saving room.


Why didn't all models receive the SI-14 hairspring? Well, I can't say. It's uncharacteristic for Omega to give features to models before the Deville, which generally receives the white glove treatment while the rest of the watches are forced to wait in line. It makes me wonder if the SI-14 hairspring performs better for some purposes and not for others. According to Omega, the SI-14 hairspring takes less work to actually use, making it odd to me that they don't use it universally. 

Omega might like to keep the SI-14 in some models and not others for purposes of market differentiation, although this doesn't make much sense in light of their expensive Deville line, generally speaking, not receiving it. However, Omega, does take the time to advertise "SI-14" on the casebacks of watches that receive it, implying that they do care that we know about it.

It's also at least possible that, like Omega claimed before, all models of the 8500 receive it now although it's not advertised. Curiously, even on the new Planet Ocean, which does receive the spring, the website's movement details don't specify the SI-14 hairspring. As far as I can tell, only the annual calendar models' information discuss it. Omega did claim that all models in 2011 and later would receive the hairspring, but my model was made in 2011 and lacks the logo on the pictograph, the writing on the caseback or the writing on the balance. Conversely, I've spent a little time looking through casebacks of various 8500 trying to get a visual cue on the hairspring itself that would reveal the difference between the anachron and SI-14. At least to my cursory inspection, the springs look exactly the same to me, unlike, say, the parachrom blue hairspring used in some Rolexes. It's possible we'll never know why Omega doesn't use it in the entire line. It's also possible we'll never know if it's already used in some models, quietly. It might be an attempt to avoid the hunt of the new model over the old one, like has been the case with the 2500D versus the 2500C. But this is all just speculation on my part. 












At any rate, the SI-14 hairspring is supposed to have excellent resistance to variations in magnetism and temperature. I won't go into great depth on it since this model doesn't have it and volumes have been written about it elsewhere by people who know more than I do.

The Aqua Terra 8500 was probably aimed squarely at the Rolex Datejust, but buyers should also consider the slightly cheaper Grand Seiko 9S65 models as well as the JLC Master Control, all of which have high-end movements and reputations for superb quality. For your convenience, the specs are as follows: 60 hour power reserve, chronometer certified, adjusted to 5 positions, internal accuracy range, qua Omega, of 4 seconds (!), "long" service interval.

Addressing each spec in turn. The 60 hour power reserve is impressive, and beats Rolex handily (50 hours) and simply annihilates the JLC (44 hours). Yet none are a match for the Grand Seiko 9S65's 72 hour power reserve, mysteriously achieved with a simple single barrel design. This is apparently the result of Seiko's proprietary Spron alloy (a different formulation of this is also used in their hairsprings) and an ultra efficient movement design. So why does Omega use by far the most complex power reserve system and only get a rather distant second place?











Well, as I alluded to above, the dual mainsprings were not really ever designed to maximize the power reserve on the 8500, but to stabilize power delivery throughout the various stages of wind. The mainsprings are sequential, not fully parallel, meaning that the "automatic" barrel, barrel 2 for those who care, unwinds on its own first, and when the output of it drops below a certain level, barrel 1 is brought in to stabilize the delivery. The result won't make much difference if you wear the same watch every day, since it will be near the optimum part of the power band, but by the same token, the shorter power reserve won't either. Omega made the conscious decision to increase accuracy low in the power reserve at the cost of maximum power reserve. How does this compare to Seiko's solution? I can't say since I don't have a 9S65 to test (feel free to send one), but I have to suspect that, in this area, it would outperform it. Seiko does have a proprietary system out now on one Credor that stores excess energy from the mainspring, only to return it when the energy drops later. That said, the vast majority of us can't afford Seiko's solution yet, so I doubt I'll be testing it anytime soon. 













My (former) roommate and I decided to test the power reserve rating together. We have the same model 8500, one in his Deville and one in my AT. He received 63.5 hours, where I received 63.25 hours. In either case, the power reserve rating was easily met and exceeded. He did not do accuracy testing on his model near the end, but I did. My watch gained 7 seconds in 62 hours (I don't just stand by the watch for the last hour waiting for it to die. Importantly, that's two hours beyond the rating, so after that is just gravy). I lament the fact that I didn't make accuracy observations on each day, so I can't determine exactly how much accuracy decreased as the power reserve down. We can postulate that the first day gained 2 seconds or less, since on an ordinary day where I wear it, laying crown up at night, it gains just under 1, whereas this would be experiencing a decreased power reserve and was dial up. If that is the case, the remaining 5 seconds would have to be divided between the following two days, and if that is the case, it was remarkably consistent. I'd rather spend my time wearing the watch than let it sit in a watch case doing power reserve testing, but when I get a new watch, I will run this test again more carefully and see where, exactly, the 7 seconds was gained. At any rate, 7 seconds over 2.5 days as the power reserve died is very impressive, and substantiates Omega's design choice in the double barrel system. We really do need to get a 9S65 in here for comparison though.

The watch is chronometer certified and adjusted to 5 positions. Not much to say about that, but it's a chance for me to post a photo that was really hard for me to take with my terrible cell phone camera. I'm pretty proud of it even though it looks awful. As far as I know, all upscale Swiss mechanicals are adjusted to 5 positions, although Seiko takes it another step to do 6. 













What is much more interesting is the internal 4 second range that Omega uses. This was reported on by WatchTime. Between my roommate and I, we've had three 8500s, all the same version, and we have carefully tracked their accuracy. The results are basically as follows: two of them, including mine, were a little under +1/day, and one of them was a little less than -1 a day. The position at which the watch sleeps does appear to affect mine, but only ever so slightly, perhaps to a quarter second. These results compare well with the many anecdotal reports on WUS, and it appears that, nearly as a matter of certainty, a new 8500 will be within +2 seconds a day. This movement has excellent consistency and resistance to positional variation. You can't cheat with this movement, or at least, I can't with mine. There's no wiping out a second gained in a day by a certain position at night. It's borderline immune to positional variance, so don't expect to even be able to visualize the difference the position makes the next day. It's something you're going to need 3 or 4 days before it's obvious. So far as I can tell, there is no positional way to get my particular watch to lose time. I have tested crown up and crown down, and it appears that on my example, crown up runs ever so slightly slower than crown down. This is contrary to WatchTime's results, but your mileage may vary. Ultimately, with a week of testing, sleeping crown up at night and worn all day, the watch gained just under a 1 second day, ending with a net total of 6 seconds even over 7 days.










I only want to add a note about the service interval. All 8500s initially received a 3 year warranty, which is above average for this segment, but a 4 year warranty was given to the SI-14 models. Eventually, the 4 year warranty was given to the entire 8500 range, even retroactively. Does this show confidence or the lack thereof in the movement? What do I look like, a mind reader?










As per the long term durability of the thing, the co-axial escapement does appear to me to be more resistant to wear than competing systems. But escapements aren't the only parts of a watch that need service. Often the automatic winding system is one of the less durable system in a watch. Here, however, the slide bearings are made of this zirconium oxide, which may, or may not, decrease wear. It certainly sounds cool. At any rate, claims that these things have some sort of 30 year service interval have been floating around WUS, and I have to say, I'm highly skeptical. What I will suggest is that it is probable the 8500 will experience less loss of accuracy over time, between service intervals. This is due in part to the reduced wear in the coaxial escapement, but it's also due to the choice to use a free sprung balance, which is less likely to have its long term time keeping affected by shock than its regulated counterpart, all things being equal. Furthermore, the mainspring barrels are both DLC coated, which according to Omega, will reduce wear on them as well.










So I speculate that the 8500 will wear very well over time. But this is speculation. We've only had 5ish years on the 8500 now, and we really need more like 10-20 to start knowing what the common points of failures are on this movement. 

While I'm on the subject, I wanted to make a note of the unique shock absorption system on the 8500, the Nivachoc system. This is a mysterious alternative to the major competitors, the Incabloc, KIF and Diashock systems. 

A quick note on shock absorption systems on mechanical watches. All modern watches, at least that I'm aware of, use some form of shock protection for the balance to prevent broken balance shafts. This is accomplished by mounting a spring over the balance that allows a little mobility, and therefore shock absorption, for the balance shaft. It's not so simple, of course, because the second job of the shock absorber is to return the balance back to its ordinary position after a shock. All modern systems appear to be a major improvement over non-shock absorbed systems.

Incabloc is by far the most common in Swiss movements because it is the one adopted by most ETA calibres. It uses two points of contact. The KIF system is used by Rolex (now using the Paraflex system) and most higher end Swiss makers, which has three points of contact. Diashock, of course, is the Japanese system designed by Seiko, which uses a very innovative (although now quite old) three point "triangular" design. Most people in the know, i.e., that know more than me, think that KIF is better than Incabloc, but at least conceptually, I prefer the Diashock over all three. I am told by watchmakers that it is the more difficult system to work with, but just looking at the thing, it seems to be the one that'd best resist shocks. But that's hardly a scientific analysis, and frankly speaking, I'm not qualified to choose a winner.

Here's my photo of the Nivachoc:







It's the little gold colored thing on top of the balance.

Here's some random person's much better photo:










Now, as to Nivachoc, I cannot find any information about it. All of the ordinary shock absorbers I can "see" how they work just by looking at them and seeing how they would flex in response to shock. Not so for the Nivachoc. I have no idea how this thing works, or why it's supposed to be an improvement over the other three. But that's what Omega's claim is. They had access to ordinary shock absorbers from Swatch Group, so they weren't under the gun to make a proprietary design. Consequently, I don't think they'd have bothered if they couldn't improve it, especially since they don't advertise the Nivachoc shock absorber. But again, speculation on my part.

For comparison, here are a few photos, not mine, of the major competing systems:










Here's Seiko's variation:









Note the dual diashock absorbers on the Grand Seiko.

I also want to say a word on the BPH of the watch. Like its predecessors, the 2500C and D, it runs at 25k as opposed to the more standard 28k. Why did the 2500 get shifted from 28k to 25k? Well, that's the subject of great debate among Omega collectors, but to be perfectly frank, I don't think we really know what we're talking about. All things being equal, low BPH movements suffer less wear and have a longer power reserve, generally at the cost of shock resistance (not in terms of toughness, but in terms of accuracy). 28k has emerged as the magic number in this era, with high end manufacturers generally taking an extreme approach, either like Seiko or Zenith, with very high BPH movements, or like IWC or Patek, will use relatively low BPH movements. Omega, oddly, chose to go somewhere in between, excepting the early 2500s and the new 9300 chronograph, which both operate at 28k. 

What we do know from the 2500s and from the 8500s is that the accuracy is excellent despite, or perhaps because of, the low BPH. It also directly contributes to the length of the power reserve. Like the 28k 9S65 has a 72 hour reserve, while the nearly identical 36k 9S85 has only a 55 hour power reserve, the 8500 at 25k has a 60 hour reserve and the 9300 at 28k has a 55 hour power reserve. We can also speculate that whatever issues were encountered in the 28k 2500s have been addressed in the 9300 chronograph model.

Personally, this choice doesn't bother me at all. In terms of seconds hand smoothness, it's very difficult to tell, looking at an 8500 in isolation, that the hand is staccato, unlike a 21k movement, which is quite obvious. When side by side to the 28k movement, it's apparent on close examination that it's slightly less smooth, but it still appears smooth to the eye. 28k, in my experience, really is a bit of a magic number because that's where my eye starts to have trouble seeing the individual beats. In fact, holding 36k movements next to 28k ones, it's actually difficult for me, personally, to tell the difference. If you're into ultra-smooth seconds hands, this model isn't for you, but that said, neither is any of the nearest competition, all of which operates at 28k. If it's not important to you, you'll probably never notice. I don't.

I got a surprising amount of questions about when the date on the 8500 changes over. The answer is, it depends on which 8500. On my model, and most others, the date begins to change over at 10:50, gets about half way there by 11:50, and completely flips at 11:59. Apparently there is an acceptable +/- 10 minute variation on these models. Conversely, the Annual Calendar models have a 5 minute acceptable variation (from midnight) and apparently take much less time to change over in general, although I haven't tested it. 
Before:









After:








*

Summary*
So how does this compare to the competition? Well, I won't speak to the aesthetics since that's an inherently personal choice, but the fit and finish is excellent and certainly better than my Ananta (although, of course, an Ananta is not the same thing as a GS). Furthermore, while the Rolex DJ has a broad variety of styles to choose from, the AT is inherently more sporty than the JLC MC and virtually any GS. Thus, depending on what you're going for, you can get basically the exact same watch in a Deville with a more subdued styling. Personally, I love both. 

Now, in terms of movements, I'm very impressed. On the numbers, it does appear to be better, overall, than the JLC MC or DJ. How does the real world performance compare? I can't really say, because there's not enough data on the JLC yet. In my view, the only horological threat in its price range is the GS. On every metric, smoothness, accuracy and power reserve it appears to outperform the 8500. However, the 8500 certainly has a longer service interval suggestion, and additionally, some factors are difficult to tell just by looking at a spec sheet, like positional variance and how accurate a watch is at low levels of power reserve. In these areas, the 8500 might very well exceed the 9S65, but I can't know until I try it for myself. To the degree that Seiko's 6 position adjustment affects the performance compared to the Swiss' overall standard of 5 I cannot say. 

Ultimately, I'm very impressed with both the watch and the movement.









*
NEW INFORMATION

On the SI-14 and Buyer's Guide
*We can now confirm that ALL NEW (at least as of June 2012) full-sized Aqua Terras have the SI-14 hairspring. My advice to you is to you is to either buy right now (6/20) and beat the price increase, buy used or hold out until the model you want gets it (or your dealer gets the new ones in stock). This appears to confirm one of my hypotheses about the SI-14 hairspring, that of the silent introduction. I believe this is to avoid "hairspring" shopping where people want the "newest" model, sort of like occurred with the 2500D/2500C Planet Oceans. That's just my guess.

How do you know if your new AT has the hairspring? Well, on the Aqua Terra, it appears Omega will not be writing SI-14 on the caseback. It does seem to appear on the pictogram card that comes with the watch. The best way to tell is to hack the watch and look very closely at the balance. SI-14 models will have SI-14 written on them.

This means that no mid-size ATs, _that we know of_, have SI-14 right now. We'll need more thorough examination as people buy more ATs and I will update this to reflect the information so that future buyers can know if they're getting the SI-14 hairspring.
*
On automatic winding
*I missed a detail on the automatic winding mechanism in the 8500. Apparently, the rotor, at least the edge of the rotor, is made from tungsten, which is substantially more dense than steel. This might increase winding efficiency.

Also, I think I misread Omega's claims on the silent automatic winding system. What I thought they meant was that you couldn't hear or feel the rotor, which again, is true of most bi-directional winders and is unremarkable. But it's also possible they meant you couldn't actually hear it winding. If that's the case, then they're right. The actual winding (of the reverse wheels, I guess) is totally silent, much quieter than say my Ananta's magic lever pawls over the pawl wheel.

What winding system is used in the 8500? It's hard for me to say since I'm not going to take it apart, but judging from Omega's description and the systems they've used in the past, I think this probably uses the reverse wheel solution, variations of which are found in most Swiss automatics (not JLC or high end IWC, but most of the others work basically the same).

I have no convenient way of testing this, but the winding does seem to be very efficient and it seems to be fully wound even after my day of just sitting and reading.


----------



## CitizenM

Edit: Fixed


----------



## RogerP

Comprehensive indeed - thanks for taking what had to be a lot of time to put that together in words and pictures. Very timely as well as I am about to close a deal on the larger version of this very watch.

Again, well done on the review.


----------



## Balidaan

Very comprehensive review! 
It will take a me a few days to digest the details of the movement though (Which is something that I am just beginning to understand).


----------



## gouverneur

Very impressive and comprehensive review from a true watch lover and a guy who clearly knows what he's talking about.


----------



## fasthandssam

Excellent. Thank you for sharing.


----------



## wristclock

Wow, nice watch and great review. I have wanted one of these ever since I laid eyes on one. Enjoy, I know I will when I get one.....oh yes, it will be mine, oh yes.....This watch has it all in my book. Sporty, fit and finish, movement, detail in the dial and hands, the list goes on and on. Such a well rounded piece.


----------



## Bahoomba

Just unbelievably great - the watch, the review, the photos. THIS is watch collecting - and watch knowledge - at its best. A huge tip of the cap.


----------



## Ramblin man

This too, is probably my next Omega. Your review and pictures certainly help confirm it. Well done! Thanks.


----------



## Stonechild

Awesome review, thanks very much for all your efort. A true benifit for all WUS members.

Jay


----------



## mleok

I just looked at the Aqua Terra and the Annual Calendar version at the Omega boutique, they are very nice watches in the metal. They are a bit on the thick side, and the 43mm Annual Calendar was probably too large for my wrist, but the regular 41.5mm and 38.5mm seem to be a more sensible size for me.

I was particularly surprised by the 12 hour quickset, which is a very nice feature. The slowness of the date change seems common with movements that have quickset local time hands that are linked to the date, and which allow you to move the date backwards and forwards by adjusting the hour hand. This is also true of my JLC Grande Reverso Duo, and my Victorinox Swiss Army Alliance Chronograph (quartz), although I don't know if a Rolex GMT IIC exhibits the same issue.

The annual calendar doesn't have the 12 hour quickset, but the date and month can be adjusted separately at the second stop. I wonder what happens with the Omega AT Annual Calendar if the date is at 31 and you adjust the month to one with less than 31 days? The Omega manual doesn't seem to say anything about this. Pity the question didn't occur to me in the store. My Baume and Mercier Hampton Annual Calendar requires you to cycle through all the days of the month to move the month forward, which is a bit of a bother, but doesn't actually take all that long.

One interesting piece of news is that they'll be releasing a GMT version of the Aqua Terra, in 43mm, with an in-house movement. It should be available by September.


----------



## CitizenM

mleok said:


> I just looked at the Aqua Terra and the Annual Calendar version at the Omega boutique, they are very nice watches in the metal. They are a bit on the thick side, and the 43mm Annual Calendar was probably too large for my wrist, but the regular 41.5mm and 38.5mm seem to be a more sensible size for me.
> 
> I was particularly surprised by the 12 hour quickset, which is a very nice feature. The slowness of the date change seems common with movements that have quickset local time hands that are linked to the date, and which allow you to move the date backwards and forwards by adjusting the hour hand. This is also true of my JLC Grande Reverso Duo, and my Victorinox Swiss Army Alliance Chronograph (quartz), although I don't know if a Rolex GMT IIC exhibits the same issue.
> 
> The annual calendar doesn't have the 12 hour quickset, but the date and month can be adjusted separately at the second stop. I wonder what happens with the Omega AT Annual Calendar if the date is at 31 and you adjust the month to one with less than 31 days? The Omega manual doesn't seem to say anything about this. Pity the question didn't occur to me in the store. My Baume and Mercier Hampton Annual Calendar requires you to cycle through all the days of the month to move the month forward, which is a bit of a bother, but doesn't actually take all that long.
> 
> One interesting piece of news is that they'll be releasing a GMT version of the Aqua Terra, in 43mm, with an in-house movement. It should be available by September.


That's really interesting per the quickset date on the annual calendar models. You know, I was wondering about that when I was pouring over the spec sheets to figure out why the date change was so slow on this model, and the spec sheet on the AC version was listed as being more "instant" than mine (I don't remember what word they used) and it also had the tighter +5/-5 minute variation from midnight. So I think this probably confirms your suspicion from your annual calendar post that watches with independent 12 hour hands, for whatever reason, are more likely to have slow date changes. I know how the date wheel/date ring mechanism works in ordinary watches, which is quite simple, but then, on that mechanism, it's incapable of going backwards, so it must be fundamentally different. If I get a chance to take apart one and figure it out, I will and see what causes this hangup. It's an annoyance, but I think the independent 12 hour hand is worth it, if just for the novelty. Plus it's kind of fun to throw it around when you set the time, because it "sticks" to the hours (you can't set it out of alignment even if you want to).

I'll look into the Rolexes with independent 12 hour hands, which should be revealing since Rolex is very proud of their near instantaneous date change mechanism (thus providing extra incentive for them to deliver on it).

As per the 31 days on the wrong month, I've got no idea. If I had to guess, if it were on a short month, it would advance the date twice, meaning it would show the next month on the 2nd instead of the 1st. But I wouldn't find out on such an expensive watch lol.

I love what I'm seeing on the new AT GMT and, money willing, I may trade in my AT to get that one. Plus, I believe it has the SI-14 hairspring.









I just love the red splash of color in GMT models. That said, while I don't mind the date window being at 6 instead of 3, it does bother me that it doesn't use the cool date window that's in mine.

Sorry to hear about that quirk on your Baumet, although, it's hard to complain about a watch that attractive with an annual calendar at its price.


----------



## H2KA

Excellent review on a great watch.. Thanks for taking the time to share this..


----------



## acello27

Very well done and written. I learned a lot.
And that is my favorite Omega.


----------



## CitizenM

I forgot to mention, my usual article rules apply: likes for everyone!


----------



## NightOwl

Wow, that was a comprehensive review. I've ready other AT8500 reviews, but yours is quite thorough and informative. I think the size is good on you although I find either the 38.5 or the 41.5 falls in the sweetspot for most wrists. Can't really go wrong with either size. What's your wrist size if you don't the question?

Funny thing about the si14 spring. My new Golf AT has the si14 symbol on the pictogram card but nothing on the caseback. Another member on the f20 has the same model but his pictogram card lacks the si14. So what kind of timetable Omega is keeping with incorporating the si14 spring into the entire AT line is anybody's guess.


----------



## lvt

One of the best reviews I've read so far. Thanks.



CitizenM said:


> I actually think the most interesting part of the 8500 was the choice to go with a double barrel mainspring. That, by itself, is not all that rare. Many watches that feature an extreme power reserve use double barrel mainsprings to achieve it. Yet Omega only obtained a very good power reserve, hardly an amazing one. One of its primary competitors, the Grand Seiko, gets 72 hours on just one spring. So why two springs?
> 
> Well, the design is apparently to try to make the release of energy more constant throughout the various states of wind. So far as my research suggests, only one mainspring is unwinding at 100%, and the second one starts releasing energy into the movement when the first one has a certain drop in output, stabilizing the output as a result. The consequence of having them not work at the same time all the time is, ultimately, a shorter power reserve than could otherwise have been achieved. On the other hand, the more constant power flow should help maintain accuracy even at low levels of power reserve. An interesting side note is that the barrels are both DLC coated, apparently for wear resistance. Whatever the case, the black barrels do look cool peaking out of the very edge of the 8500.


Nice projection, but it's not enough to convince me about the existence of dual-barrel setup.

Do Rolex and Grand Seiko movements have less constant energy flow than Omega's 8500 ? Or they have an industrial secret to use on single-barrel setup that Omega doesn't know or can't achieve despite of millions dollars spent in R&D ?

Other 8xxx calibers like 8601 or 8611 so we can't really say that the dual-barrels setup helps in regulating energe, because saying so makes people think that other single-barrel Co-ax movements have less constant power flow. Aren't they all COSC certified ? So why only cherish the 8500 with dual-barrels if it's not to just fill the available space and make it an excellent marketing argument ?


----------



## CitizenM

NightOwl said:


> Wow, that was a comprehensive review. I've ready other AT8500 reviews, but yours is quite thorough and informative. I think the size is good on you although I find either the 38.5 or the 41.5 falls in the sweetspot for most wrists. Can't really go wrong with either size. What's your wrist size if you don't the question?
> 
> Funny thing about the si14 spring. My new Golf AT has the si14 symbol on the pictogram card but nothing on the caseback. Another member on the f20 has the same model but his pictogram card lacks the si14. So what kind of timetable Omega is keeping with incorporating the si14 spring into the entire AT line is anybody's guess.


Totally agree on the size. In fact, the sizes are so close that they may not even need both. I think I have a 6.5 inch wrist, but I always forget that for some reason.

Another member, who had the black model introduced last year, received a card with the SI-14 logo on it. I'm pretty sure these cards are misplaced and the watch doesn't have the SI-14. As far as we know, the only way to really confirm is to hack the watch (or let it die) and look very closely at the balance.

Models with SI-14 have this written on it:










This is the one on mine and other non SI-14 balance wheels:









Now I did check mine, and mine is a very recent model from 2011, post Omega's official "all 2011 models will receive the SI-14 hairspring" and mine did not have the SI-14 writing. However, the lack of writing doesn't mean, necessarily, that it doesn't have the hairspring. I can't see any visual difference between the springs, so it's entirely possible that they quietly introduce them into the AT. Actually, if you don't mind, could you hack yours and take a look? It would be really helpful in figuring out this SI-14 thing.


----------



## CitizenM

lvt said:


> One of the best reviews I've read so far. Thanks.
> 
> Nice projection, but it's not enough to convince me about the existence of dual-barrel setup.
> 
> Do Rolex and Grand Seiko movements have less constant energy flow than Omega's 8500 ? Or they have an industrial secret to use on single-barrel setup that Omega doesn't know or can't achieve despite of millions dollars spent in R&D ?
> 
> Other 8xxx calibers like 8601 or 8611 so we can't really say that the dual-barrels setup helps in regulating energe, because saying so makes people think that other single-barrel Co-ax movements have less constant power flow. Aren't they all COSC certified ? So why only cherish the 8500 with dual-barrels if it's not to just fill the available space and make it an excellent marketing argument ?


Yes, in all probability, they do have a more "round" power band than the 8500. I would have to test them to confirm this.

But yes, Seiko does have an industrial secret (well, I suspect it's a patent, but it could be a trade secret) in the Spron alloy that it uses in its mainsprings. It is apparent throughout the range that the Spron alloy outperforms all competitors. It gets 72 hours on a single barrel, but it also gets 60 hours on a single barrel on its entry level 6R15C.

But I think you're trying to oversimplify an incredibly complex subject. The power consumption of various movements are very different. The co-axial escapement will change the power requirements wildly, and many believe that it needs more torque than comparable escapements to function.

Furthermore, the efficiency of the entire movement must be taken into consideration to determine the power reserve.

And lastly, an increase in BPH will result in a decrease in power reserve, all things being equal (they're not, it's the general rule).

I'm not sure why you mention Rolex, because Rolex actually does have a substantially lower power reserve than the Omega, meaning that even assuming that they had equally flat energy output, it would still be outperformed by Omega's setup.

As per Omega's spending power, different designers come up with different solutions to problems, or sometimes simply value certain traits over others. As I write above, it is probably that Omega valued consistent energy output over maximum power reserve. The design of the double barrel system, in sequence, will, in fact, stabilize power output. These are not mounted in parallel. I don't want to repeat everything I already wrote about this above, but much of the time, both barrels are not in play. After some period of inactivity, when the energy output from barrel 2 drops below a certain level, a mechanism engages barrel one to release its energy and stabilize the output, at which time they operate in parallel until the watch dies (or, I suppose, but do not know for sure, barrel 2 might "die" first).

Which solution is better? Well, I can't say. First off, we can't hold every variable constant because we're using radically different movement designs, and additionally, what do you want to achieve, maximum power reserve or maximum consistency of delivery? And, even then, I'd have to have two identical movements with the different mainspring solutions and compare them side by side to see what improvement the double barrel system makes, if any.

As I pointed out above, Seiko apparently agrees with Omega because they have already developed a conceptually similar system in Credor called the Torque Return system. This was announced in 2009, not long after the announcement of the 8500, so it's unclear who approached movements this way first, or if either is novel. It's possible that there are older exotic movements that have already used similar systems.

Anyway, in an article of Watch Around: "When mechanical watches are fully wound, they deliver morepower than is needed to maintain the watch at a steady rate. The
Torque Return feeds this extra power back into the mainspring,
extending its nominal 55-hour power reserve by seven hours or
12.7%. It's devastatingly simple. An extra wheel train (green)
runs off the mainspring barrel (blue) and rewinds the spring via
the ratchet-wheel (pink). 
The closed loop system returns 20% of the power to the mainspring during the first 35 hours. Then a cam (yellow) on the
power-reserve indicator disengages the Torque Return via the
hooked arm, relieving the mainspring from its burden and allowing it to maintain the rate of the watch for another 27 hours." Referring to the new Credor system.

It's a more elegant system, I think, than Omega's, but again, without some serious side by side testing, I'm not prepared to offer an opinion on which is more efficient.

"because saying so makes people think that other single-barrel Co-ax movements have less constant power flow" Well, yes, that's the point. They ought to think there is less consistent power flow. Because there is.

"Aren't they all COSC certified ? So why only cherish the 8500 with dual-barrels if it's not to just fill the available space and make it an excellent marketing argument ?"

Well, first, no, they're not all COSC certified. No Grand Seiko is allowed to receive COSC rating because they are Asian. Second, not all COSC watches perform exactly the same, and it's curious that you'd suggest that they do. The 8500, for instance, easily outperforms a chronometer grade ETA equivalent in every available metric. For readers from other threads, I did look into the range that ETA achieves before sending top grades off for testing, and it's an 8 second range, as opposed to the 8500's 4 second range.

Anyway, just because you're COSC rated doesn't automatically mean you're as good as it's ever possible to be. The Grand Seiko is excellent proof of this, since all modern Grand Seikos, and almost every Grand Seiko ever made (i.e., prior to the existence of COSC, which was created in order to ban Japanese people from competing in Switzerland) easily exceeds the COSC rating, at a minimum, by a range of 2 seconds, and at best, by 4 seconds.

If you remain a skeptic of the double barrel setup, I think there are good reasons for it. Is the extra complication worth the benefits? Is Seiko's solution better? Those are all arguments worth entertaining. To speculate that the double barrel setup was created as a marketing tool seems very improbable. For one, no one outside of WUS is aware of what a mainspring is, much less a double barrel mainspring, or even what a power reserve even is. Second, my empirical data suggests that the system works. Third, the power reserve was increased by 25% over the single barrel 2500 predecessor. Fourth, a great many high end brands already use double barrel mainsprings and no one has suggested that they're just offering marketing.

I will endeavor to get a Grand Seiko this year and if I can do that, I promise an unbiased head to head testing between them. I'll try to get a COSC ETA and my roommate should have a few 2500Cs laying around for me to work with. None of us have Rolexes or JLCs though, so for the foreseeable future, those will get left out (not by choice. I'd love to try those watches out).


----------



## lvt

Just to add a note to my latest post, when I said about COSC I mean that the 86xx are also COSC certified like the 85xx, I didn't refer to the GS.


----------



## NightOwl

CitizenM said:


> Totally agree on the size. In fact, the sizes are so close that they may not even need both. I think I have a 6.5 inch wrist, but I always forget that for some reason.
> 
> Another member, who had the black model introduced last year, received a card with the SI-14 logo on it. I'm pretty sure these cards are misplaced and the watch doesn't have the SI-14. As far as we know, the only way to really confirm is to hack the watch (or let it die) and look very closely at the balance.
> 
> Models with SI-14 have this written on it:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> This is the one on mine and other non SI-14 balance wheels:
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Now I did check mine, and mine is a very recent model from 2011, post Omega's official "all 2011 models will receive the SI-14 hairspring" and mine did not have the SI-14 writing. However, the lack of writing doesn't mean, necessarily, that it doesn't have the hairspring. I can't see any visual difference between the springs, so it's entirely possible that they quietly introduce them into the AT. Actually, if you don't mind, could you hack yours and take a look? It would be really helpful in figuring out this SI-14 thing.


I never knew the si14 was written right on the wheel. I hacked my AT and low and behold, Omega's pictogram card didn't lie to me. I can't seem to work a camera as effectively as you but here it is. I forgot to wipe off the watch, so please excuse the lint. 







FWIW, mine was just off the UPS truck new. The watch was being delivered to the AD as I walked in the door. The manager went into the back to open up the store's newly arrived shipment in order to show me this particular watch. Thus, I'm assuming (.... guessing?) mine was fresh off the production line.


----------



## CitizenM

I know you're well read up on mainspring design, but this might help others:


----------



## CitizenM

NightOwl said:


> I never knew the si14 was written right on the wheel. I hacked my AT and low and behold, Omega's pictogram card didn't lie to me. I can't seem to work a camera as effectively as you but here it is. I forgot to wipe off the watch, so please excuse the lint.
> View attachment 740761
> 
> FWIW, mine was just off the UPS truck new. The watch was being delivered to the AD as I walked in the door. The manager went into the back to open up the store's newly arrived shipment in order to show me this particular watch. Thus, I'm assuming (.... guessing?) mine was fresh off the production line.


Wow, awesome photo.

Well, I guess that settles it then. The 2012 Golf, at least, is receiving the SI-14 hairspring, and we can confirm my earlier speculation that Omega would choose to quietly introduce SI-14 to the AT line.

Man, now I want a newer one.


----------



## fasthandssam

thread delivers


----------



## CitizenM

That's what we do here at WUS. Make the headlines lol. The Omega world will be abuzz tomorrow with the official news of the SI-14 hairspring in the AT.


----------



## fasthandssam

Well I am just so impressed by the response time. As quickly as I was learning about the Si-14 stamp, reports start filtering in.


----------



## CitizenM

fasthandssam said:


> Well I am just so impressed by the response time. As quickly as I was learning about the Si-14 stamp, reports start filtering in.


And hopefully we'll get some news from Blueeyedninja on his new Grand Seiko SBGR061. He said he synced it yesterday and would begin getting data points. Maybe NightOwl would oblige and gather some data too and we can begin to get data points of the 8500A and 8500B and see if there's any discernible difference in the real world.


----------



## fasthandssam

CitizenM said:


> And hopefully we'll get some news from Blueeyedninja on his new Grand Seiko SBGR061. He said he synced it yesterday and would begin getting data points. Maybe NightOwl would oblige and gather some data too and we can begin to get data points of the 8500A and 8500B and see if there's any discernible difference in the real world.


I have to admit that I was a bit surprised with a few of the recent reports about GS relative poor accuracy, especially in light of what you've demonstrated from the 8500. But that is one risk of such a small data pool- it is easy to get distorted results. I'm actually starting to wonder if the 8500 may not be a more accurate movement than the GS. The question then becomes- why is the Seiko guaranteed to a higher accuracy officially? I'm sure that if Omega could guarantee a tighter range in accuracy they would- imagine the Swatch marketing machine promoting something that reliably beats COSC standards? Anyways these things have been on my mind. Eventually I hope to be making a similar purchase decision so I am particularly interested in the performance of these competing movements.


----------



## drunken monkey

Regarding the twin barrel; I quite like the suggestion made by another member here, that Omega's use of twin barrels could also be to do with simple packaging.
Two smaller barrels takes up less radial space than a single large one and when you have a large-ish balance wheel on a bridge to stick in there too, movement real estate becomes a premium.

Maybe two barrels just fit better than a single large one.


----------



## acdelco

Thanks for the nice review. Great watch...


----------



## Bubblemunche

'Comprehensive' is an understatement. This is such a great review, it makes me feel proud of being a AT8500 owner.


----------



## dbakiva

Great posts, CitizenM. I came to your thread last night, and started it, but my weary eyes told me to check back in the morning when I could assimilate it. Great work. Although I went a different way with my recent acquisition, I really like and respect Omega (an older Seamaster GMT is my daily wearer). After reading your excellent post, I am even more impressed with the AT and the 8500 movement, as I am with your analysis. 

Wear yours in very good health and isochronism.


----------



## CitizenM

drunken monkey said:


> Regarding the twin barrel; I quite like the suggestion made by another member here, that Omega's use of twin barrels could also be to do with simple packaging.
> Two smaller barrels takes up less radial space than a single large one and when you have a large-ish balance wheel on a bridge to stick in there too, movement real estate becomes a premium.
> 
> Maybe two barrels just fit better than a single large one.


It's certainly possible that was a factor, but I think the most telling fact about the double barrels is that they don't operate in parallel, or at least not in the beginning. There's no reason you can't just hook up two barrels and let them both unwind simultaneously. Omega chose to go the sequential route. So even if they chose double barrels for reasons of space, the choice to use sequential as opposed to parallel would have been motivated for concerns of power delivery.


----------



## CitizenM

fasthandssam said:


> I have to admit that I was a bit surprised with a few of the recent reports about GS relative poor accuracy, especially in light of what you've demonstrated from the 8500. But that is one risk of such a small data pool- it is easy to get distorted results. I'm actually starting to wonder if the 8500 may not be a more accurate movement than the GS. The question then becomes- why is the Seiko guaranteed to a higher accuracy officially? I'm sure that if Omega could guarantee a tighter range in accuracy they would- imagine the Swatch marketing machine promoting something that reliably beats COSC standards? Anyways these things have been on my mind. Eventually I hope to be making a similar purchase decision so I am particularly interested in the performance of these competing movements.


Well, remember, Seiko can't be COSC certified, so they may just advertise their internal accuracy stats, whereas since Omega does send all co-axials off to chronometer testing, it gets the same COSC rating that everyone else gets, no matter how accurate. So Omega really has no motivation to advertise that stat, for one, because then they'd basically be accountable for it if there was an anomalous model.

But we just have two not very accurate GSes out of hundreds here. Most people have reported excellent accuracy. And, at any rate, they do have a smoother seconds hand and a longer power reserve than I do. I really will try to get one for comparison.

Ultimately, the 8500 is a much newer calibre, both in terms of year released and in terms of the approach to design. I dare say it's an Anti-Seiko design. When it comes to mechanical watches, Seiko doesn't like to play with new designs. They find a design they like, and then they refine it endlessly until they pound it into submission and make it perform. Almost all of the success of the 9S is attributable, in my opinion, to the materials used, the precision in making the parts (MEMS is the most precise process anywhere in the world) and the human element in assembling, finishing and tuning the movements. But a byproduct of this approach is that there's very little risk involved. How will silicon hairsprings perform in 20 years? I have no idea. I'm not particularly worried either, since I think Omega is a trust worthy source when it comes to their commentary on the parts they use, but it's a concern you wouldn't have with the Seiko. Additionally, because the 9S has been out around 14 years, there's not going to be many surprises there.

I'd really, really like to go nuclear and bring in Seiko's big guns, the 9S85, for testing. I just don't know how I could do it without selling the AT first, but that may be what I have to do in order to test it.


----------



## Marts7

First post. Just thought I'd say I think this forum is great, I like taking in all thoughts and opinions (some of which I adopt as my own) from a very educated community. I have no brand loyalty, I just like watches and hopefully my own personal wealth will continue to grow at the rate I'd like to collect pieces!

I thought I'd post some of my first thoughts on my newly acquired 8500 (new from AD as of this past Saturday)...

Love the watch, and love the green accents of the 'golf' variety. I had my eye on the 41.5mm teck grey dial for months and actually thought the golf version looked pretty tacky in pictures (perhaps part of the reasoning is that I've always associated green with Rolex? Who knows...?). When I saw it in the metal, I really changed my opinion. As everyone on this thread is fully aware, the dial on the AT8500 is very dynamic in varying light conditions, and I found the green minute track/seamaster font to contribute to this effect immensely. On many occasions, the green isn't even perceptible - and in others it really pops. I guess there was a certain amount of uniqueness which appealed to me. So, the story goes... I went in to my AD fully ready to purchase the Teck Grey 41.5mm AT, saw the green version/black dial (the other thing I like about this model being the sharpness/contrast of the black over the grey) and proceeded to give it about 30 minutes wrist time in store. I went home and sat on the thought of going with the golf for about 2 weeks, went back into my AD and gave it another 30 minutes wrist time to confirm what I had played over in my head for a fortnight. I understand that the green may not be for everyone, but it spoke to me. Here are a few pictures (excuse the camera phone!).

I can confirm that my watch is fitted with the Si-14, which is indicated on the pictogram but not on the case-back. I would take a photo to confirm but I'm in the midst of a timing accuracy exercise and don't want to hack the watch.

Speaking of the accuracy, I wasn't able to synchronise with an atomic clock until 9:00am Monday morning so I've only just gone beyond 48 hours in my efforts. Thus far it appears to be picking up +4 seconds per day :-s. I was hoping for something a little more closely regulated but it may still be in the midst of its own break in period (and it is within COSC specs). The good thing is that there doesn't appear to be any isochronism to speak of. It's literally picking up 1 second every 6 hours and overnight I've done face up, and then crown up. For me, better fast than slow - and, truth be told, it seems like every auto I've ever owned has run fast on me. Must be something in my daily usage... I'll continue to monitor the accuracy in a couple of other positions but it's likely that over the life of this watch I will default to either face up or crown up (when I'm not thinking it always ends up in one of the two). I suppose that if the +4 holds for a couple of months I could take it into a watchmaker or my AD to see if they could regulate tighter for me but I'm kind of loathe to open up a new case that is otherwise perfect if not a little bit fast. I'm probably getting ahead of myself anyway and I don't really want to fall into a no-nit-too-small-to-pick mindset.

Bottom line, great satisfaction thus far. Just love the look.

















And two wrist shots... (sorry about the glare from the overhead fluorescent)


----------



## lvt

+4 sec per day is well within COSC but FYI my automatic watch with an ETA 2836-2 COSC runs +/-2 sec per day since 2 years in a row, now it's in the first half of the third year with the same accuracy, and I've seen a lot of watches with ETA COSC movements run equally accurate or even better than mine. No wonder why several watch brands are confident enough to make $5,000 watches with ETA movements.


----------



## jilgiljongiljing

The the OP, great review. This is the sort of sales talk the SA's need to do to push watches, I am almost tempted to go to the dealer right now to pick one up 

BUt I haz no monies....%#$#@R


----------



## Marts7

Yeah, I know LVT. I have an Aquatimer (non-COSC) that runs +4/week based on every-other-day usage (which won't be the case for the next month or two while I get my AquaTerra fix on).


----------



## CitizenM

Marts7 said:


> First post. Just thought I'd say I think this forum is great, I like taking in all thoughts and opinions (some of which I adopt as my own) from a very educated community. I have no brand loyalty, I just like watches and hopefully my own personal wealth will continue to grow at the rate I'd like to collect pieces!
> 
> I thought I'd post some of my first thoughts on my newly acquired 8500 (new from AD as of this past Saturday)...
> 
> Love the watch, and love the green accents of the 'golf' variety. I had my eye on the 41.5mm teck grey dial for months and actually thought the golf version looked pretty tacky in pictures (perhaps part of the reasoning is that I've always associated green with Rolex? Who knows...?). When I saw it in the metal, I really changed my opinion. As everyone on this thread is fully aware, the dial on the AT8500 is very dynamic in varying light conditions, and I found the green minute track/seamaster font to contribute to this effect immensely. On many occasions, the green isn't even perceptible - and in others it really pops. I guess there was a certain amount of uniqueness which appealed to me. So, the story goes... I went in to my AD fully ready to purchase the Teck Grey 41.5mm AT, saw the green version/black dial (the other thing I like about this model being the sharpness/contrast of the black over the grey) and proceeded to give it about 30 minutes wrist time in store. I went home and sat on the thought of going with the golf for about 2 weeks, went back into my AD and gave it another 30 minutes wrist time to confirm what I had played over in my head for a fortnight. I understand that the green may not be for everyone, but it spoke to me. Here are a few pictures (excuse the camera phone!).
> 
> I can confirm that my watch is fitted with the Si-14, which is indicated on the pictogram but not on the case-back. I would take a photo to confirm but I'm in the midst of a timing accuracy exercise and don't want to hack the watch.
> 
> Speaking of the accuracy, I wasn't able to synchronise with an atomic clock until 9:00am Monday morning so I've only just gone beyond 48 hours in my efforts. Thus far it appears to be picking up +4 seconds per day :-s. I was hoping for something a little more closely regulated but it may still be in the midst of its own break in period (and it is within COSC specs). The good thing is that there doesn't appear to be any isochronism to speak of. It's literally picking up 1 second every 6 hours and overnight I've done face up, and then crown up. For me, better fast than slow - and, truth be told, it seems like every auto I've ever owned has run fast on me. Must be something in my daily usage... I'll continue to monitor the accuracy in a couple of other positions but it's likely that over the life of this watch I will default to either face up or crown up (when I'm not thinking it always ends up in one of the two). I suppose that if the +4 holds for a couple of months I could take it into a watchmaker or my AD to see if they could regulate tighter for me but I'm kind of loathe to open up a new case that is otherwise perfect if not a little bit fast. I'm probably getting ahead of myself anyway and I don't really want to fall into a no-nit-too-small-to-pick mindset.
> 
> Bottom line, great satisfaction thus far. Just love the look.
> 
> View attachment 741966
> 
> 
> View attachment 741967
> 
> 
> And two wrist shots... (sorry about the glare from the overhead fluorescent)
> View attachment 741969
> 
> 
> View attachment 741970


Awesome. Yeah the Golf doesn't look super great to me in photos, but it's the one model I haven't seen in person, so I could definitely shift if I could see it in the flesh.

+4 is technically within the official (COSC) rating, but it is a little anomalous in the grand scheme of 8500s, which seem to vary between +2 and -1. I've spent a lot of time trying to figure the "wear in" theory of watches, and currently believe it _does _exist in the majority of mechanical watches, but there are people that disagree. I can say that I've personally observed it on my watches, and as you can see, I test the accuracy very thoroughly. One day I'll buy a timing machine and get really good numbers.

Well, it's good to know that all Golfs, at least, are receiving the SI-14...or at least, it seems like all Golfs. This makes sense since it's the or one of the most recent models. Now the question is: do all new "big" AT 8500s have it, or just the Golf? In either case, do any of the midsized models (like mine) have it?

And the even bigger question, as your experience suggests, is does the SI-14 hairspring make a real world difference or have any tradeoffs.

As per your particular experience, if you wind it all the way up on Day 1, wear it, let it sleep crown up, in that circumstance (I consider best case circumstance) does it still gain +4?

Personally, it's a little disappointing (the +4) but I don't think it warrants messing with. Besides, we don't really know if the 8500s experience any wear in, or I guess I should say, if they do I haven't seen it, but maybe yours will slow down to a more leisurely +3.


----------



## Athram

Brilliant review. Took me a while to get through it. I'm sure it took you a while to write it


----------



## CitizenM

The original post is updated at the end with new information on the automatic winding system and on the SI-14 discovery. I hope that people can refer to this as a bit of a catchall when they need to learn about the AT, so I'll update it from time to time as I get new data.


----------



## Marts7

Hi CitizenM

At my AD, all three of the 41.5mm versions were fitted with the Si-14 hs (that is, grey, silver, golf). Maybe they had received a recent shipment? I can't confirm one way or another as the mid-size was never in my hand or on my wrist (and i didn't have the foresight to check or ask).

As you say, the +4 was a little dissapointing as I hoped it would be a little better, but I really don't plan on farting around with it. I will continue with my current accuarcy expirement for 14 days (that's my standard test when i get a watch) but after that I will run it flat and then wind it all the way up as you suggest. The AD knew I was coming in and actually sync'd the watch for me in advance but it wasn't to an atomic clock and therefore I didn't have an entirely clean slate to start from. I was really hoping for a +1 (or less) with no isochronism. Whatever... it's good enough and if the 4 is entirely stable over the life of the watch (until the first servicing) I'll just hack it once a month and go back 2 minutes.


----------



## CitizenM

Marts7 said:


> Hi CitizenM
> 
> At my AD, all three of the 41.5mm versions were fitted with the Si-14 hs (that is, grey, silver, golf). Maybe they had received a recent shipment? I can't confirm one way or another as the mid-size was never in my hand or on my wrist (and i didn't have the foresight to check or ask).
> 
> As you say, the +4 was a little dissapointing as I hoped it would be a little better, but I really don't plan on farting around with it. I will continue with my current accuarcy expirement for 14 days (that's my standard test when i get a watch) but after that I will run it flat and then wind it all the way up as you suggest. The AD new I was coming in and actually sync'd the watch for me in advance but it wasn't to an atomic clock and therefore I didn't have an entirely clean slate to start from. I was really hoping for a +1 (or less) with no isochronism. Whatever... it's good enough and if the 4 is entirely stable over the life of the watch (until the first servicing) I'll just hack it once a month and go back 2 minutes.


Thanks for the heads up on the SI-14 hairsprings....man, I might have to upgrade soon lol, just got this one.

Hopefully yours will settle in nicely.


----------



## RogerP

Congrats on the new piece Marts7. I would not mess with a watch running at +4 / day, and doing so consitently.

Thanks again for all the great info CitizenM. If you have a link to the Watch Time article on this watch (or this movement), please post or PM - it did not come up for me on a site search.

Roger


----------



## Raza

Man, you _love _Seiko. In a review about an Omega, you went on and on about Seiko.

Nice review, though.


----------



## Verdict

CitizenM, is the case brushed?

I saw the latest iteration of the Speedy Pro in person lately, and I thought it was a little too flashy/shiny for my tastes. Is the Seamaster the same way?


----------



## mleok

Verdict said:


> CitizenM, is the case brushed?
> 
> I saw the latest iteration of the Speedy Pro in person lately, and I thought it was a little too flashy/shiny for my tastes. Is the Seamaster the same way?


The thing which struck me most about the new co-axial Speedy Pro was how thick it was.


----------



## charlieboy89

meh i cant really tell the difference from your unboxing thread and this "comprehensive review" of yours :think:

NOT! that was awesome review :-!

^To verdict, Did you look at the photos??


----------



## CitizenM

RogerP said:


> Congrats on the new piece Marts7. I would not mess with a watch running at +4 / day, and doing so consitently.
> 
> Thanks again for all the great info CitizenM. If you have a link to the Watch Time article on this watch (or this movement), please post or PM - it did not come up for me on a site search.
> 
> Roger


Sure, here you go:

http://www.watchtime.at/archive/wt_2007_05/WT_2007_05_142.pdf

This was by FAR the most helpful article on the internet in figuring out how the 8500 was designed. As far as I'm aware (I read many reviews before buying mine) people simply don't mention a lot of the changes in the 8500, perhaps because there's so much fanfare for the co-ax and the double barrel mainspring. Great article.


----------



## RogerP

Merci.


----------



## CitizenM

Raza said:


> Man, you _love _Seiko. In a review about an Omega, you went on and on about Seiko.
> 
> Nice review, though.


I do love Seiko, but the reason Grand Seiko needed a presence in my article was because the 9S65 is really the biggest competitor in this price range. There are few other excellent calibres, the Rolex 3135, JLC 889 and the IWC 80111 which are basically in the same price range and all essentially three hander autos. In my view, the 9S65 and 9S85, at least in terms of the numbers I have access to, are the real standouts in this price range, along with the 8500. Based on those numbers, I felt that I didn't need to make a case for the 8500 versus the other three movements (the IWC, in particular, not because it's not a good movement, but because the Ingenieur, which is the only one vaguely in this price range, is such a tool watch it just didn't belong overall, hence I didn't spend any time on it here). If one of them falls into my lap though, I will certainly give a comparison because they're all certainly very good--but only the Seiko calibres had better stats, which, other than basic design choices, is all I have to go on for these. I think the 9S line is also an interesting comparison because Seiko takes the polar opposite approach as Omega to movement making/design, at least, that used in the 8500. Ultra refined and finely crafted traditional watchmaking versus very edgy, high-tech design choices mass produced largely by robots. Which performs better? I can't wait to find out.


----------



## CitizenM

Verdict said:


> CitizenM, is the case brushed?
> 
> I saw the latest iteration of the Speedy Pro in person lately, and I thought it was a little too flashy/shiny for my tastes. Is the Seamaster the same way?


The case is both brushed and mirror polished. Basically, most "up" facing facets of the case are mirror polished, and most lateral ones are fully brushed. The finishing, except for perhaps the lugs where they contact the top of the bracelet, is really well done.

I would say that the AT line is quite subdued, particularly my gray model, so I don't think it'd be too flashy. The orange Planet Ocean seamaster, lol, on the other hand, may be another story.


----------



## RogerP

^^^ True, but a guy that finds a _Speedy Pro _too flashy isn't likely to find the Aqua Terra any less so.

Roger


----------



## CitizenM

mleok said:


> The thing which struck me most about the new co-axial Speedy Pro was how thick it was.


The 9300 calibre is pretty massive. The 8500 isn't necessarily huge, but it's definitely not thin either.

The thing that really worries me about the 9300 is what the service bill is going to be on it. You could buy a pretty nice watch for the cost of a service, I expect...but who knows, maybe I'm wrong.


----------



## CitizenM

charlieboy89 said:


> meh i cant really tell the difference from your unboxing thread and this "comprehensive review" of yours :think:
> 
> NOT! that was awesome review :-!
> 
> ^To verdict, Did you look at the photos??


Lol, see, I told you had some more to write on it.


----------



## billiybop

A great review of a beautiful watch. And a good idea to post on the Public forum. 
This just could be the review to influence me to go back to Omega.


----------



## RogerP

Anyone who thinks a Speedy 9300 is thick needs to try on a POC 9300 - it will alter your perspective on the Speedy pretty muh instantly. I don't find the AT 8500 to be thick at all. It is very nicely proportioned.

Roger


----------



## Verdict

CitizenM said:


> The case is both brushed and mirror polished. Basically, most "up" facing facets of the case are mirror polished, and most lateral ones are fully brushed. The finishing, except for perhaps the lugs where they contact the top of the bracelet, is really well done.
> 
> I would say that the AT line is quite subdued, particularly my gray model, so I don't think it'd be too flashy. The orange Planet Ocean seamaster, lol, on the other hand, may be another story.


Oh that's nice to hear, guess I'll have to check it out now.

The Speedy Pro I saw at the AD was so...flashy. It caught light a little too well, and the pushers were like little diamonds in the way they gave off light. I can't tell if I was impressed or overwhelmed.



charlieboy89 said:


> ^To verdict, Did you look at the photos??


Yes, I did, but the way a watch looks in person is vastly different than it does in a photo IMO.


----------



## lvt

The 9300 has double-barrels setup and a column wheel driven chronograph, it's difficult to make it smaller than its current size.


----------



## CitizenM

I wore a Rolex DJ in white gold with the fluted bezel briefly once, and I was blinded by its shiny disco ball-esque nature. I didn't buy it.


----------



## napel

Man, with a write up like that how could you not want to buy one?


----------



## khj94704

Great read. I must bide my time and let my completely frivolous purchase fund recover while waiting out this Si-14 transitional period.


----------



## mleok

RogerP said:


> Anyone who thinks a Speedy 9300 is thick needs to try on a POC 9300 - it will alter your perspective on the Speedy pretty muh instantly. I don't find the AT 8500 to be thick at all. It is very nicely proportioned.
> 
> Roger


The AT 8500 is a reasonable size, particularly since it's really a dressy sporty watch hybrid, and can therefore get away with being slightly on the thick side. But just because the Planet Ocean Chronograph is an even more monstrously large watch than the Speedmaster Pro 9300 does not change the fact that the Speedy Pro 9300 is substantially thicker (and somewhat bigger) than its predecessor, and as such feels like a very different watch on the wrist. It's clear that the thickness is very much due to the 9300 movement, since the display caseback has the movement literally popping out of the midcase.


----------



## CitizenM

khj94704 said:


> Great read. I must bide my time and let my completely frivolous purchase fund recover while waiting out this Si-14 transitional period.


My own article revealed to me I didn't wait long enough


----------



## khj94704

CitizenM said:


> My own article revealed to me I didn't wait long enough


I really don't think the silicon hairspring is a big deal and I wouldn't discount the value of actually having and enjoying a nice watch for all that time while my money is just a barely tangible number sitting in a bank account with a pathetic 0.8% APY.


----------



## Aerofish

Thanks for a great review! What a beautiful complete time piece. I don't think there is a person in known universe who just falls totally in love with that date window! IMO it is always these tiny details that moves a watch into that rarified iconic level of nirvana! |>|>


----------



## CitizenM

Lol, maybe it's time for me to switch into a GS so I don't have to worry about these upgrade things anymore.


----------



## lvt

What's the practical point of the Si-14 (let alone the marketing stuffs) ?


----------



## CitizenM

There is no practical point to any watch in the world.

At any rate, if we believe the marketing hype, SI-14 is much more resistant to changes in temperature, immune to magnetism (as much as any other matter, anyway), and can be formed in nearly a perfect shape from the get go.

It's that latter part that has me curious. By Omega's own little youtube commercial, it seems like SI-14 hairsprings would be much CHEAPER to make than delicately forming, and fine tuning, custom steel alloys. As I understand it, you don't have to bend or form any part of the hairspring. It just comes out ready to go. 

But there's all sorts of stuff I don't know about that goes into that process, so I'm probably missing something. 

In the real world, will it make any substantial difference? No, probably not. As you can see, my anachron model is apparently outperforming its SI-14 counterpart (in this instance). But really, it's not the "ordinary" oscillations where the quality of the hairspring is called into play. It's how it plays with less predictable factors, like temperature, magnetism, shocks and varying levels of energy out of the mainspring.

But you know, many of the best brands in the world are still using custom metallic alloys, like JLC, Seiko, Patek and so on, so it's not as if it's a world beating thing. At least two of those claim better accuracy...but it seems like the 8500 is just a movement obsessed with stability above all else...with the notable exception of beat rate. 

I've GOT to get a 9S85 in here, and whatever else I can get my hands on, for testing.


----------



## acdelco

Hey Lvt, many can see you don't particularly like modern Omega...it must be just 
EXHAUSTING to be you to try to come up with posts in threads like this. Why not try giving it a rest and relax : )



lvt said:


> What's the practical point of the Si-14 (let alone the marketing stuffs) ?


----------



## lvt

acdelco said:


> Hey Lvt, many can see you don't particularly like modern Omega...it must be just
> EXHAUSTING to be you to try to come up with posts in threads like this. Why not try giving it a rest and relax : )


Posting on WUS is one of my most relaxing activities, how could you call it *exhausting* ?

@CitizenM : I think you made a good point there, there is no practical point to any watch...

However, we shouldn't forget that there have been many practical inventions made to watches from the last decades, for example sealed water-resistant case, auto-winding, quick date-setting... and they are much more useful than making a new escapement or concocting a new material just to use them for marketing.


----------



## mleok

CitizenM said:


> There is no practical point to any watch in the world.
> 
> At any rate, if we believe the marketing hype, SI-14 is much more resistant to changes in temperature, immune to magnetism (as much as any other matter, anyway), and can be formed in nearly a perfect shape from the get go.


That seems like a perfectly practical reason to me. The main challenge of serial manufacturing of precision machines, like a mechanical watch, is in achieving sufficient manufacturing tolerances that parts are easily interchangeable, such that the performance of the machine is predicable, with a low variance. For the manufacturer, it's a dream to be able to produce parts that are cheaper to manufacture, and are more reliable.


----------



## CitizenM

lvt said:


> However, we shouldn't forget that there have been many practical inventions made to watches from the last decades, for example sealed water-resistant case, auto-winding, quick date-setting... and they are much more useful than making a new escapement or concocting a new material just to use them for marketing.


Yes, I'm sure it's all just marketing (nevermind that they're not marketed on the Aqua Terra, even the ones that have them).


----------



## CitizenM

mleok said:


> That seems like a perfectly practical reason to me. The main challenge of serial manufacturing of precision machines, like a mechanical watch, is in achieving sufficient manufacturing tolerances that parts are easily interchangeable, such that the performance of the machine is predicable, with a low variance. For the manufacturer, it's a dream to be able to produce parts that are cheaper to manufacture, and are more reliable.


I take Omega's claims regarding SI-14 as basically true (although there may be undisclosed downsides, I haven't made my mind up on that), but I'm curious as to why, if it's so great, a version of it isn't used for a mainspring?

When Seiko developed the Spron alloy, they wasted no time in creating an alternative formulation for mainsprings, and that got them to 72 hours on a single barrel.

For people reading this and wondering what all the fuss is about making hairsprings ready to go instead of forming them, here's a nice Seiko diagram that address both my Spron analogy and why, I think, SI-14 hairsprings are probably cheaper to make than the anacron ones:


----------



## Nishant

What a fantastic review ..
Well Done.


----------



## mleok

CitizenM said:


> I take Omega's claims regarding SI-14 as basically true (although there may be undisclosed downsides, I haven't made my mind up on that), but I'm curious as to why, if it's so great, a version of it isn't used for a mainspring?
> 
> When Seiko developed the Spron alloy, they wasted no time in creating an alternative formulation for mainsprings, and that got them to 72 hours on a single barrel.
> 
> For people reading this and wondering what all the fuss is about making hairsprings ready to go instead of forming them, here's a nice Seiko diagram that address both my Spron analogy and why, I think, SI-14 hairsprings are probably cheaper to make than the anacron ones:


Well, Omega wasn't the first company to develop the silicon balance spring, so they probably were able to learn from some of the pioneering work on Spiromax silicon hairsprings in the Patek Philippe Advanced Research models.










The manufacturing process for hairsprings is much more precise and delicate, as can be seen in the Seiko photo you attached. In particular, the correct shape and curvature of the hairspring is essential for it to "breathe" concentrically, which is important for isochronism. It is also the magnetization of the hairspring that most dramatically affects timekeeping.

In contrast, the mainspring requires much less precision, so the manufacturing costs are probably lower, and the advantages of silicon in terms of precision manufacturing, and antimagnetic properties is much less pronounced. One additional point is that the hairspring is not as tightly coiled, in contrast to the mainspring. So, it's possible that silicon springs are unable to to be compressed as much, which would then compromise the power reserve. My guess is that the cost-benefit ratios for silicon mainsprings make them much less compelling.

There's a good discussion of the advantages of silicon hairsprings here:

Ludwig Oechslin on MIH tests with silicon hairsprings

If you look at the silicon hairspring, the width is not even throughout the length of the spring, which improves the ability of the spring to breathe, and does not rely on changing the natural curvature of the spring in the traditional approach.


----------



## RogerP

I don't think the Si14 is hype, but I also think it's practical impact on the performance of the movement will be minimal. How much better timekeeping would you expect as comapared to what you are getting now? It's not like there's a whole lot of room for improvement.

mleok - of course the automatic Speedy 9300 is thicker (as well as wider) than the hand-wind Speedy Pro. If you find it too thick / mostrously thick / whatever - that's fine. Buy and wear what you like. The Speedy Pro isn't going anywhere. In the context of modern sports chronographs, however, it would be hard to make the case that the Speedy 9300 stands out as being particularly big, much less monstrously huge.


----------



## mleok

RogerP said:


> mleok - of course the automatic Speedy 9300 is thicker (as well as wider) than the hand-wind Speedy Pro. If you find it too thick / mostrously thick / whatever - that's fine. Buy and wear what you like. The Speedy Pro isn't going anywhere. In the context of modern sports chronographs, however, it would be hard to make the case that the Speedy 9300 stands out as being particularly big, much less monstrously huge.


I haven't really been on the market for a sports chronograph, so I'll take you word for it that the Speedy 9300 is not atypical for the genre. For reference, the Speedy 9300 is 16mm thick and has a 44.5mm diameter, compared to the original at 13mm and 42mm, respectively.


















There's a good article on the Speedy 9300 compared to the hand-wind here:

A Week On The Wrist: The Omega Speedmaster Co-Axial.Chronograph - Watches Worth Knowing About - HODINKEE

These are some photos of the movement.










and this photo illustrates what I mean about the movement sticking out of the midcase.


----------



## Likestheshiny

My problem in reading about the shiny new 8500 movement is that I prefer the _old _dial on ATs. Threads like this just remind me what I'd be giving up to have a dial I like more.


----------



## Raza

mleok said:


> I haven't really been on the market for a sports chronograph, so I'll take you word for it that the Speedy 9300 is not atypical for the genre. For reference, the Speedy 9300 is 16mm thick and has a 44.5mm diameter, compared to the original at 13mm and 42mm, respectively.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> There's a good article on the Speedy 9300 compared to the hand-wind here:
> 
> A Week On The Wrist: The Omega Speedmaster Co-Axial.Chronograph - Watches Worth Knowing About - HODINKEE
> 
> These are some photos of the movement.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> and this photo illustrates what I mean about the movement sticking out of the midcase.


It's not 2012 vs. 1967, it's Coaxial vs. Professional.


----------



## RogerP

^^^ Yep - I thought they blew the label on that photo.


----------



## lvt

Raza said:


> It's not 2012 vs. 1967, it's Coaxial vs. Professional.


It's rather 54 jewels vs 17 jewels.


----------



## CitizenM

mleok said:


> Well, Omega wasn't the first company to develop the silicon balance spring, so they probably were able to learn from some of the pioneering work on Spiromax silicon hairsprings in the Patek Philippe Advanced Research models.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> 
> The manufacturing process for hairsprings is much more precise and delicate, as can be seen in the Seiko photo you attached. In particular, the correct shape and curvature of the hairspring is essential for it to "breathe" concentrically, which is important for isochronism. It is also the magnetization of the hairspring that most dramatically affects timekeeping.
> 
> In contrast, the mainspring requires much less precision, so the manufacturing costs are probably lower, and the advantages of silicon in terms of precision manufacturing, and antimagnetic properties is much less pronounced. One additional point is that the hairspring is not as tightly coiled, in contrast to the mainspring. So, it's possible that silicon springs are unable to to be compressed as much, which would then compromise the power reserve. My guess is that the cost-benefit ratios for silicon mainsprings make them much less compelling.
> 
> There's a good discussion of the advantages of silicon hairsprings here:
> 
> Ludwig Oechslin on MIH tests with silicon hairsprings
> 
> If you look at the silicon hairspring, the width is not even throughout the length of the spring, which improves the ability of the spring to breathe, and does not rely on changing the natural curvature of the spring in the traditional approach.


The article is really interesting, but counterintuitive. For one thing, and this isn't a passive aggressive remark towards you, I promise, but they only have one custom made silicon hairspring, which isn't, I presume, roughly identical to the SI-14. Actually, Omega and Patek aren't even the only ones using it. Damasko does too. And even then, it's just a single model. So the results aren't especially revealing, or at least, I can't know if they're especially revealing, towards the Omega.

But, worse yet, the tests appear quite unimpressive to me. The silicon hairspring is noted to be extremely fragile, and far more susceptible to changes in temperature than the nivarox hairspring. I guess that's another little complaint I have about the study. Which nivarox hairspring? They're not all the same.

From the data we have here, the principle advantages are, plain and simple, to be primarily found in cost cutting.

What we need is some good, unbiased testing data comparing a known quantity (say, Nivarox 2, which is excellent and very common) to the SI-14 hairspring we're working with here. And a few samples of each.

I have no doubt that Omega improved upon the design and materials used in this primitive prototype, but how much? And, if it's true that anacron (anachron) is some wizbang super hairspring material, might it outperform SI-14?


----------



## CitizenM

RogerP said:


> I don't think the Si14 is hype, but I also think it's practical impact on the performance of the movement will be minimal. How much better timekeeping would you expect as comapared to what you are getting now? It's not like there's a whole lot of room for improvement.
> 
> mleok - of course the automatic Speedy 9300 is thicker (as well as wider) than the hand-wind Speedy Pro. If you find it too thick / mostrously thick / whatever - that's fine. Buy and wear what you like. The Speedy Pro isn't going anywhere. In the context of modern sports chronographs, however, it would be hard to make the case that the Speedy 9300 stands out as being particularly big, much less monstrously huge.


The key to hairspring materials and design isn't to achieve a great daily rate in ideal conditions. You can regulate any old ETA with a run of the mill nivarox hairspring to a great daily rate if the conditions are nice. The key difference between mediocre and great hairsprings are how they deal with unusual conditions. Very hot or cold weather, exposure to magnetism, variations in the amount of energy supplied by the mainspring and so on. So a mediocre hairspring material and design (the design is at least as important) will experience greater deviations in amplitude than will better competitors.

I guess, the long and short of it is, in the day to day, the SI-14, even assuming it delivers on all the hype, won't make any noticeable difference...but its accuracy might not change much in those other situations.

Mleok's article was very revealing of some of the potential weaknesses though...I need to get better data.


----------



## RogerP

CitizenM said:


> The key to hairspring materials and design isn't to achieve a great daily rate in ideal conditions. You can regulate any old ETA with a run of the mill nivarox hairspring to a great daily rate if the conditions are nice. The key difference* between mediocre and great hairsprings are how they deal with unusual conditions*. Very hot or cold weather, exposure to magnetism, variations in the amount of energy supplied by the mainspring and so on. So *a mediocre hairspring material and design* (the design is at least as important) will experience greater deviations in amplitude than will better competitors.
> 
> I guess, the long and short of it is, in the day to day, the SI-14, even assuming it delivers on all the hype, won't make any noticeable difference...but its accuracy might not change much in those other situations.
> 
> Mleok's article was very revealing of some of the potential weaknesses though...I need to get better data.


1) Would you describe the hairspring in your current AT 8500 as "mediocre"?

2) I get the benefit of increased resistance to magnetism - but in nearly 20 years collecting watches, I have had a watch become magnetized exactly.... once. The fix was both quick and inexpensive (how often do we get to say that?). So the benefit to me of that particular attribute is again, rather minimal.


----------



## CitizenM

Also, as to mainspring material, it's possible that the properties that apparently make SI-14 advantageous for the hairspring set it back for mainsprings. Nonetheless, I don't see why they're not playing with new materials for the mainspring, or if they are, why aren't they making a bigger difference. A variation of Seiko's Spron, and a few other tweaks (importantly, none to the BPH etc) took their watch from 50 to 72 hours. Now, I grant you that you could surely have increased the power reserve by altering the mainspring using the existing material, whatever that was, but that was nearly a 50% increase in power reserve with no massive design revisions. Why aren't others playing with mainspring materials as much. 

I'd really like to look into the design of the IWC 5000 series. A 7+ day power reserve on a single barrel design. Conversely, it may explain their lackluster accuracy. On the other hand, A. Lange uses a double barrel to achieve 72 hours on some of their models, and both the IWC and ALS are using paltry low-beat rates. Seiko is achieving 72 hours, world beating accuracy and an ordinary BPH, apparently primarily as a result of the Spron alloy. Long story short, Seiko's got some magic going on that I don't fully understand here. Heck, it achieves many of the 8500s power reserves (i.e., 9300, annual calendar models and so on) which is 55 hours, even at 36000 bph.


----------



## CitizenM

RogerP said:


> 1) Would you describe the hairspring in your current AT 8500 as "mediocre"?
> 
> 2) I get the benefit of increased resistance to magnetism - but in nearly 20 years collecting watches, I have had a watch become magnetized exactly.... once. The fix was both quick and inexpensive (how often do we get to say that?). So the benefit to me of that particular attribute is again, rather minimal.


From whatever I could find, the anachron hairspring is the top of the range from Swatch Group, but I can't find any objective numbers on it. If it is top of that range, it should be world class, I'd imagine probably comparable to the new PB hairspring in some Rolexes.

You're right, magnetism isn't that big of a deal, but it's a constellation of factors.

To be perfectly honest, no one is ever going to appreciate the difference between the hairsprings in their watches, assuming it's a decent one. I'm interested in it on an intellectual level.


----------



## CitizenM

Ok, I did some digging, and the only other use of anachron I can find is actually in Breguet. This kind of makes sense, not just in terms of corporate ownership, but they also use balance wheels of an identical material (beryllium free alloys) as the 8500. 

I guess I could do worse than having some Breguet-esque parts in my watch.


----------



## mleok

CitizenM said:


> The article is really interesting, but counterintuitive. For one thing, and this isn't a passive aggressive remark towards you, I promise, but they only have one custom made silicon hairspring, which isn't, I presume, roughly identical to the SI-14. Actually, Omega and Patek aren't even the only ones using it. Damasko does too. And even then, it's just a single model. So the results aren't especially revealing, or at least, I can't know if they're especially revealing, towards the Omega.
> 
> But, worse yet, the tests appear quite unimpressive to me. The silicon hairspring is noted to be extremely fragile, and far more susceptible to changes in temperature than the nivarox hairspring. I guess that's another little complaint I have about the study. Which nivarox hairspring? They're not all the same.
> 
> From the data we have here, the principle advantages are, plain and simple, to be primarily found in cost cutting.
> 
> What we need is some good, unbiased testing data comparing a known quantity (say, Nivarox 2, which is excellent and very common) to the SI-14 hairspring we're working with here. And a few samples of each.
> 
> I have no doubt that Omega improved upon the design and materials used in this primitive prototype, but how much? And, if it's true that anacron (anachron) is some wizbang super hairspring material, might it outperform SI-14?


I wouldn't be surprised that the main advantage is cost savings, since I would imagine that the adjustment of the hairspring is the single biggest bottleneck in the production of the Omega 8500 calibre. I think there is a measure of art and exceptional skill in adjusting the curvature of the hairspring so that it breathes correctly, and I can't imagine it is easy to find a large number of skilled watchmakers able to do this sensitive, essential, but repetitive task.

I imagine even adjusting the variable inertia balance wheel is easier, since there are only two independent degrees of freedom which need to be tweaked, and a computer can be used in the testing process to suggest what changes to make.

The fragility of the silicon is probably what prevents it from being used in the mainspring. As for how a long power reserve is achieved with a single barrel design in the IWC, I was under the impression that this is due to IWC dramatically reducing the power loss in the gear train, which allows them to replace the main spring with a much weaker main spring, which is much longer and thinner.


----------



## CitizenM

I'm sure that the Cal. 5000 is very efficient, but is it like, 300% more efficient?

Don't get me wrong, there's no mystery to storing a lot of energy in a spring, but not delivering way too much in the beginning and way too little (comparatively) at the end is the mystery...but perhaps it's not a mystery, insofar as they're not known for their accuracy, so it may just be that simple.

As per the price, I certainly have no problem with reducing production costs, but what is the real substantive advantage of the SI-14 spring insofar as the consumer concerns. Of course, no one disputes that it'll be basically immune to magnetism, but frankly, I'm not blown away by Omega's demonstration of SI-14's resilience. It's very good, don't get me wrong, but Seiko's Spron already did that like a decade ago.

Here's food for thought: these two hairsprings were stretched out to four CM. The second spring is the pre-Spron alloy, which I would imagine was probably as good as anything else out there (it was used in the 9S55 Grand Seiko calibres, after all).










Like Omega's demonstration, Spron shows no deformation after being severely stretched. That isn't to say SI-14 isn't impressive in this regard, but that those results are obtainable, and already have been obtained, with non-exotic materials that, it would appear to me, are less fragile, at least based on the data we have.


----------



## Tmcgeo39

Totally appreciate the time. A big part of the watch world are forums, pictures, reviews, etc...

This adds some great content.

Nice watch as well. Well balanced in many ways. It was in the final running for me recently.


----------



## CitizenM

Tmcgeo39 said:


> Totally appreciate the time. A big part of the watch world are forums, pictures, reviews, etc...
> 
> This adds some great content.
> 
> Nice watch as well. Well balanced in many ways. It was in the final running for me recently.


Which one did you end up getting?


----------



## georges zaslavsky

very good indepth review of the 8500 citizen m|>


----------



## Tmcgeo39

I went with a GS SBGR053


----------



## CitizenM

Tmcgeo39 said:


> I went with a GS SBGR053


Awesome, how's the accuracy?


----------



## Tmcgeo39

Accuracy is pretty darn good. I havent tracked in a while but it was running consistent -1-2 a day. While on it never seemed to lose anything. The power reserve, i believe directly tied to the new mainspring material, at 72hrs makes for a nice feature as well. Allows it to be put aside for the weekend and be ready to go Monday. Although i must admit other than the gym or hike, i usually wear it.


----------



## CitizenM

Tmcgeo39 said:


> Accuracy is pretty darn good. I havent tracked in a while but it was running consistent -1-2 a day. While on it never seemed to lose anything. The power reserve, i believe directly tied to the new mainspring material, at 72hrs makes for a nice feature as well. Allows it to be put aside for the weekend and be ready to go Monday. Although i must admit other than the gym or hike, i usually wear it.


Yes, the Spron alloy is incredible. Both in terms of mainsprings and hairsprings, the little data we have on it seems superb. And it accomplishes all of that in a much simpler design than my Omega.

A GS MUST be next in my collection. I'm thinking one of these three, although one is a spring drive which would make my desire to test all these things sort of pointless:








9R65 SD...so it's just so incomparable to ordinary mechanicals it doesn't even warrant testing. But it makes my heart skip a beat.








(S65, same movement as yours, all titanium. Definitely the best value I'm looking at right now.








And then there is, of course, the piece de resistance wit the 9S85 hi-beat movement. But man is it expensive.


----------



## NightOwl

Another Si14 update, if it hasn't been established already. I was killing some time after lunch with my wife today when I decided to drop into my AD (the same one where I recently bought my AT golf) to kill some time while the wife got her nails done. Anyway, we got to talking about the Si14 upgrade and he said that the 38.5 Aqua Terra, black dial with white lettering and numbering, does in fact have the Si14 spring. I checked out the hang tag and the pictogram card myself, and sure enough there was the symbol. I couldn't check for the symbol on the actual spring because he plastic sticker was still on the back, but I'm inclined to believe the pictogram card and hang tag. This 38.5 black AT and my AT golf came to the AD in the same UPS shipment last week. Curiously, he also got in a grey 38.5 AT in last week's shipment but the grey AT lacked the Si14 symbol on the hang tag and pictogram card.


----------



## CitizenM

NightOwl said:


> Another Si14 update, if it hasn't been established already. I was killing some time after lunch with my wife today when I decided to drop into my AD (the same one where I recently bought my AT golf) to kill some time while the wife got her nails done. Anyway, we got to talking about the Si14 upgrade and he said that the 38.5 Aqua Terra, black dial with white lettering and numbering, does in fact have the Si14 spring. I checked out the hang tag and the pictogram card myself, and sure enough there was the symbol. I couldn't check for the symbol on the actual spring because he plastic sticker was still on the back, but I'm inclined to believe the pictogram card and hang tag. This 38.5 black AT and my AT golf came to the AD in the same UPS shipment last week. Curiously, he also got in a grey 38.5 AT in last week's shipment but the grey AT lacked the Si14 symbol on the hang tag and pictogram card.


Thanks for the update!

As helpful as that is for the thread, I feel more and more:


----------



## mleok

Watch collecting is about the journey, not the destination.


----------



## NightOwl

CitizenM said:


> Thanks for the update!
> 
> As helpful as that is for the thread, I feel more and more:


Well, it still appears that only the black dial 38.5 AT has the Si14 spring, so far. It seems you're pretty enamored with the grey dial. If getting the Si14 spring meant getting a dial you're not in love with, it's probably better to go with the more pleasing dial regardless of contents of the watchguts.


----------



## CitizenM

NightOwl said:


> Well, it still appears that only the black dial 38.5 AT has the Si14 spring, so far. It seems you're pretty enamored with the grey dial. If getting the Si14 spring meant getting a dial you're not in love with, it's probably better to go with the more pleasing dial regardless of contents of the watchguts.


Lol I don't really care, I like all three colors, although my favorites were gray and white. Got a deal on the gray and my roommate had owned the white so it was something different, so I ran with that.

Well, maybe this is the excuse I need to sell it and check out a GS. They're basically the same design as they were in 1968 lol.


----------



## CitizenM

Oh just a few little tiny updates on the watch. I find myself a lot happier with the size today. I just had to get over my ridiculously huge Ananta and get used to it. Now, I think I'd have been just as happy with the 41, but why don't they just make a single 39.5mm model? 38's a little too small, 41's a little too big. Anyway, The size of the 38 wouldn't keep me away from it at all but I probably could have gone with the bigger one and been fine too.

As per the accuracy, the thing is just ridiculously rock solid. It's almost dead on +6 (I won't speculate to tenths of a second) per 7 days. It's basically impervious to what I do. Wear it a little, a lot, sleep dial up, crown up, it basically doesn't care.


----------



## Doboji

Amazing post, and review... I can feel my brain vibrating from the knowledge flowing in. I also have another dozen browser tabs open to related readings..

One small point... my reading suggests that Top and COSC rated ETA(2824,2892,7750) movements actually use the Anachron hairsprings rather than the Nivarox...


----------



## lvt

Doboji said:


> Amazing post, and review... I can feel my brain vibrating from the knowledge flowing in. I also have another dozen browser tabs open to related readings..


In case you don't know, Ctrl + Tab lets you navigate between tabs and Ctrl + F1 closes the current tab


----------



## CitizenM

Doboji said:


> Amazing post, and review... I can feel my brain vibrating from the knowledge flowing in. I also have another dozen browser tabs open to related readings..
> 
> One small point... my reading suggests that Top and COSC rated ETA(2824,2892,7750) movements actually use the Anachron hairsprings rather than the Nivarox...


It's possible. Maybe I'm using old data. They used to use either Nivarox 1 or 2 hairsprings, but I noticed that a new Bremont someone posted today was listed with anachron, but it was also a modified ETA cal. so I figured they just ordered one. Do you have a reference somewhere to what the current ETA line uses?


----------



## Doboji

CitizenM said:


> It's possible. Maybe I'm using old data. They used to use either Nivarox 1 or 2 hairsprings, but I noticed that a new Bremont someone posted today was listed with anachron, but it was also a modified ETA cal. so I figured they just ordered one. Do you have a reference somewhere to what the current ETA line uses?


Heres one link, I found the same info through multiple sources, so I have to assume its tru at this point.

ETA grades - WatchOtaku


----------



## CitizenM

Doboji said:


> Heres one link, I found the same info through multiple sources, so I have to assume its tru at this point.
> 
> ETA grades - WatchOtaku


Very interesting. I looked for hours to find out more about anachron and couldn't learn anything about it, other than that it was also used by Breguet. I wonder how it evaded me. But it appears its compositions and features are still mysterious.

One of the strange things I've noticed about the SI-14 hairspring in my research (since writing the original article) is that, on Omega's official website and press releases, I can't find any information that claims the SI-14 has better temperature resistant properties. Much of the hyper surrounding SI-14 has included that line, but Omega is not officially substantiating it. This may correlate with the tests Mleok cited earlier, where the thermal properties of silicon (not SI-14, whatever that is) were very poor compared to an ordinary Nivarox 2 hairspring. Later silicon hairsprings were given coatings that endowed them with thermal resistance, but to what degree I don't know. Maybe comparable, maybe even superior, but it could still be weak in that area. No doubt SI-14 is better than that test material since it's had much more development behind it.

What I'd really like to do is buy a new AT8500 with the SI-14 hairspring and test them in terms of variance instead of overall accuracy. But I'd have to take a pretty serious financial hit to pull that off.


----------



## lvt

CitizenM said:


> What I'd really like to do is buy a new AT8500 with the SI-14 hairspring and test them in terms of variance instead of overall accuracy. But I'd have to take a pretty serious financial hit to pull that off.


Why bother ? I don't think another AT with the Si-14 would perform better then yours now, the Si-14 is made for better resistance to magnetism, it doesn't mean that it makes the movement run more accurate.

What are the magnetism resistance ratings of the Si14 vs non-Si14 watches ?


----------



## NightOwl

I just realized there is something missing in your comprehensive review. 

Strap options. 

Maybe it's been done to death in other threads or you're more of a oem bracelet kind of guy, but the AT looks great on a strap. Could be helpful to go over strap options for those who are interested in the 38.5 since it takes a 19mm strap instead of the more widely available 20mm.


----------



## CitizenM

lvt said:


> Why bother ? I don't think another AT with the Si-14 would perform better then yours now, the Si-14 is made for better resistance to magnetism, it doesn't mean that it makes the movement run more accurate.
> 
> What are the magnetism resistance ratings of the Si14 vs non-Si14 watches ?


You might be right, but we'll never know if I don't do it lol. I'm sure it'll outperform anachron magnetically, no one doubts that. There are a few other claims though, like that SI-14 doesn't deform over time (may or may not be true...it's still a pretty brittle substance) and that it's highly resistant to shocks (I believe this is due to extremely low weight) and that the manufacturing process allows for match-perfect hairsprings every time. That last part is probably going to be responsible for any improvements in terms of isochronism if any exist.

The big mystery for me is the thermal performance. The test that Mleok posted showed a primitive silicon hairspring vastly outperformed by a humble Nivarox 2 in terms of thermal performance. No doubt silicon hairsprings have improved in the 8-9 following years to SI-14's commercial introduction, but how much? I notice that Omega offers a complete looking list of performance increases in their SI-14 hairsprings, but on their press releases and the website, resistance to thermal variations wasn't one of them.

But the point of upgrading to the SI-14 is more about satisfying my psychological issue with having just bought something that was upgraded, no matter how insignificantly, a couple weeks afterwards, with the slight objective benefit of giving me something to test.


----------



## CitizenM

NightOwl said:


> I just realized there is something missing in your comprehensive review.
> 
> Strap options.
> 
> Maybe it's been done to death in other threads or you're more of a oem bracelet kind of guy, but the AT looks great on a strap. Could be helpful to go over strap options for those who are interested in the 38.5 since it takes a 19mm strap instead of the more widely available 20mm.


That's a really good point, with the only issue being that I don't know anything about straps lol. I wish my roommate were on WUS because he's obsessed with them...he always buys his Omega with the factory bracelet, usually also a factory strap, and then two or three more aftermarket leather straps. He's really into like, customizing his Omegas for each day for what he's wearing.


----------



## Marts7

I've got my one week (or 168 hour) accuracy report on my AT 8500 Golf. Here are the results thus far (I plan on running for another 7 days - basically for no other reason that it gives me an excuse to pause and appreciate my new watch daily at 9:00am!):

Watch was sync'd on Monday June 18th @ 9:00am according to www.atomic-clock.org.uk (my net nanny here at work prevents java script from running the NIST & UNSO timing).

24 hours (Tuesday 9:00am) = *+4 sec* (face up for ~6 hours) Daily Gain = *+4 sec
*48 hours (Wednesday 9:10am) = *+9 sec* (crown up for ~ 10 hours) Daily Gain = *+5 sec
*72 hours (Thursday 9:00am) = *+13 sec *(crown down for ~ 8 hours) Daily Gain = *+4 sec
*96 hours (Friday 9:15am) = *+18 sec *(face down for ~ 9 hours) Daily Gain = *+5 sec
*120 hours (Saturday 9:02am) = *+22 sec *(12 up for ~12 hours) Daily Gain = *+4 sec
*144 hours (Sunday 9:15am) = *+27 sec* (6 up for ~8 hours) Daily Gain = *+5 sec
*168 hours (Monday 9:10am) = *+31 sec *(face up for ~10 hours) Daily Gain = *+4 sec

*Based on the +4, then +5 rhythm of the watch thus far I'm going to go out on a very short limb and say that the watch is basically running +4.5/day regardless of which position I lay it to rest in. you'll also notice that the usage patterns are kind of all over the map as well (anywhere from 12 hours wrist time to 18 hours). I hope it tightens up a bit but it is very reassuring to see that there are no isochronistic tendencies to speak of thus far. As for the Si-14 argument... I have no idea if that particular piece is playing a part in the results I'm seeing or not.

On a complete tangent to the discussion - I still love how the watch looks and having it on my wrist makes me smile (the most important thing IMO).

***EDIT*** - for the record I was not attempting to track any partial seconds gained each day. Therefore, I wouldn't have been tracking/estimating 10ths of a second. I believe it is, in fact, running at (or very close to) +4.5/day. Not alternating +4 and then +5. Past experience says tracking "half seconds" isn't very true to the exercise if you're using a naked eye and that it's better to be cognisant of the fact it's running partial seconds fast or slow and then use at least a weeks worth of summed results to verify what your eye was seeing.


----------



## CitizenM

Thanks for the data. It seems just slightly less stable than mine, but with such small differences, I don't think we can come to any conclusions regarding the SI-14 hairspring. It is odd though that it's running 4 seconds fast in general, just given the ordinary experiences with the 8500. I don't expect that it's the result of the hairspring, but perhaps the robots were filling slightly sick that day or something. I wish we could create an accuracy database and get enough data points that we could identify patterns.


----------



## CitizenM

Sorry to bring this to the top after the thread is tired out, but I'm re-running the power reserve test again today but this time with accuracy measurements, and I'll be adding them into this particular comment as it goes, finally updating the main post.

What's interesting is that in only 12 hours, it has somehow gained 2 seconds (??). The first go round it gained 7 seconds total over 2.5 days...obviously at this rate, that's not obtainable, so I wonder if something interesting happens in the interim. That puts it in for +4/day unworn, which really is still quite good, but I'm confused.

Watch is still dial up, in a watch case protected from most external interference at ordinary room temperature (70ish F).

Ok, I'm about 20 minutes away from the first 24 hours but it seems to have stabilized for whatever reason. It gained 1 more second for a total of +3. This puts it much more in the running for the original +7 seconds, although at current rates, that'll be +8 perhaps 9 assuming a constantly rate of 2.5 days.

I'll keep measuring it every 12 hours to get a better picture of what's going on.

This data will be useful to me in the future when I compare it to competing approaches to isochronism.

Ok, +5 after 36 hours. Gaining a little faster than last time by all appearances.

Ok, +6 as of 48 hours. Looks like it's stabilized at +1/12 hours dial up at decreasing power reserve. It's still not on track to hit its +7 from the first test though, so maybe something interesting is going to happen.

Alright, the final result for this run was 8 seconds. This is pretty much in line with the 7 seconds of the first testing. But now I have data for every 12 hours. So in 12 hour increments, it goes:

1: +2
2: +1
3: +2
4: +1
5: +2
(in 12 hour increments)

So the interesting data points here are 1-3. I speculate that at some point in the first 36 hours, that second mainspring is kicking in and stabilizing the powerband and thus is actually _decreasing _the time gained as the watch winds down. Predictably, the rate increases right before it dies. Still, this is impressively stable.

These are exactly the numbers I wanted to see. There has been a lot of speculation over the double barrel mainspring approach used in the 8500, but this appears to validate it. Not only do we see excellent consistency at various states of wind, we also can, I hypothesize, see the variation in rate in the period before barrel 1 kicks in.


----------



## Marts7

Nice CitizenM...

I completed my 14 day (336 hour) timing accuracy on my 8500 and it held the same form as my one week test (posted above). Basically, that is, it alternated between +4 and +5 seconds every other day regardless of resting position or usage. As mentioned above, I actually percieved the watch to be gaining half seconds every other day. So, anyway... extremely stable at +4.5 seconds per 24 hours (63 seconds total over 336 hours). I'm comfortable with this. More tightly regulated, sure that would be gravy but I also take solace in the fact that I can do with it as I please and not incur any, otherwise, avoidable inaccuracies.

I'm running the power down (in a watch case) right now and last i checked (about 8am this morning or 32 hours into "power cycling") it was keeping the same +4.5 seconds/24 hours. Pretty solid.


----------



## CitizenM

Awesome, how'd the watch do in the run down? PR and accuracy? 

Thanks for testing your watch too.


----------



## 152067

Hi,

I just got my new AT8500 for four days - love it ;-) 

Although it does not have any reference to the Si-14 hairspring on the housing neither on the pictogram card I could see the very small "Si 14" on the springs wheel (?).

Maybe that is interesting for someone.

patte


----------



## Orex

CitizenM said:


> Anyway, in an article of Watch Around: "When mechanical watches are fully wound, they deliver morepower than is needed to maintain the watch at a steady rate. The
> Torque Return feeds this extra power back into the mainspring,
> extending its nominal 55-hour power reserve by seven hours or
> 12.7%. It's devastatingly simple. An extra wheel train (green)
> runs off the mainspring barrel (blue) and rewinds the spring via
> the ratchet-wheel (pink).
> The closed loop system returns 20% of the power to the mainspring during the first 35 hours. Then a cam (yellow) on the
> power-reserve indicator disengages the Torque Return via the
> hooked arm, relieving the mainspring from its burden and allowing it to maintain the rate of the watch for another 27 hours."


Interesting solution - 12.7% extra power is quite alot for a single barrel design. But, if I am not wrong, this is applied within a Spring Drive movement. I believe the Tri-syncro-regulator is able to regulate a wider range of torques ( more anisochronous springs) than a purely mechanical escapement. I am not sure the solution will be so effective in a purely mechanical watch. Do you know if there are applications of it on mechanical GS?

Would be interesting to know the difference in torque between fully winded and almost zero power reserve on 8500. Do you have any data on this?


----------



## CitizenM

patte said:


> Hi,
> 
> I just got my new AT8500 for four days - love it ;-)
> 
> Although it does not have any reference to the Si-14 hairspring on the housing neither on the pictogram card I could see the very small "Si 14" on the springs wheel (?).
> 
> Maybe that is interesting for someone.
> 
> patte


The writing on the balance is the most important indicator--if you've got that, you've definitely got SI-14, whereas if your pictogram said it but the balance didn't, you wouldn't.


----------



## CitizenM

Orex said:


> Interesting solution - 12.7% extra power is quite alot for a single barrel design. But, if I am not wrong, this is applied within a Spring Drive movement. I believe the Tri-syncro-regulator is able to regulate a wider range of torques ( more anisochronous springs) than a purely mechanical escapement. I am not sure the solution will be so effective in a purely mechanical watch. Do you know if there are applications of it on mechanical GS?
> 
> Would be interesting to know the difference in torque between fully winded and almost zero power reserve on 8500. Do you have any data on this?


The SD movement is essentially unaffected by the amount of power in the mainspring (assuming it's not too little to move the gears, obviously). But I believe it would be effective in a mechanical. I think, in effect, it does almost exactly the same thing Omega's double barrels in sequence do, so it should have a very similar effect of making the "top" of the powerband more similar to the "bottom" of it. I'm not sure if we'll ever see it on a 9S though, unfortunately, since mechanical movements are really the ones that need it.


----------



## CitizenM

I wanted to stop in for a quick update. I've been amazingly busy the last few weeks so I have not kept good (by which I mean precise) tracking of time, although I do check the accuracy at least once per day. I mention this because it has not gained or lost a second, or even half a second, in over three days now. In fact, while I can't remember when I exactly set it last, it was more than two weeks ago, and is +8 right now. So for whatever reason, it appears mine has settled in to a nearly flawless accuracy. No idea if it'll last, but the trend has been improved for long enough that I thought it warranted an update.

To test to make sure the accuracy has improved and by how much, I set it again Sunday the 22nd at about 6 pm. I'm writing this here because as bad as my mind is right now I know I'll forget by week's end.

Ok, it's 7:30, checking in on day 1, absolutely no observable deviation since setting it 25 hours ago.

7:00, day 2, absolutely no observable deviation since setting it two days ago.

6:00, day 3, absolutely no observable deviation for three days.

Ok, missed day 4.

8:00, day 5, +1 second. I think it's because I left it dial up a lot yesterday, but that might just be a coincidence.

6:45, day 6, +1 second.

8:00, day 7, +1 second.

Well, I'm happy to report that a trend I was noticing over the last few weeks, but wasn't carefully scrutinizing, has been confirmed. The 8500 has had the "wear in" effect for me, for whatever reason, and has now settled down to a very, very consistent, 1 second per week. I noticed this the week before too but since I didn't write it down, and the results were too good to be true, I didn't want to jump to conclusions. Anyway, very impressive. I'll keep track of it on a week to week basis now and see if it really does hit +4/month or +5/month, either of which, of course, would be incredible.


----------



## Orex

I heard that the coaxial escapement suffers abit from the same flaws as the detent - difficult to self start and sensitive to shocks. Did you observed any problems with 8500 about this? Does it needs a swing to start or just self start if it has sufficient power?


----------



## CitizenM

Orex said:


> I heard that the coaxial escapement suffers abit from the same flaws as the detent - difficult to self start and sensitive to shocks. Did you observed any problems with 8500 about this? Does it needs a swing to start or just self start if it has sufficient power?


No, as far as I know, the 8500 has no issues regarding this. I think you may be recalling the old 2500 models that predate it, which apparently had a problem of stopping quasi-randomly. Even that was quite rare though.

The 8500 has been around for about 4 years, and it's developed a good track record so far. I think Omega learned from its mistakes in the 2500, which was a heavily modified ETA calibre. The 8500 didn't have the design restrictions because it was built from the ground up around the co-axial.


----------



## CitizenM

Update, and I couldn't edit my original post for some reason. 

I wanted to specify that I was wrong about the white gold on the movement. It turns out that, at least in regard to the rotor, it's rhodium plated tungsten. As far as I know, only the hands and indices are solid white gold (also rhodium plated). I misread the Watchtime article (reading about the 8501, which DOES use a solid gold rotor, but not white gold).


----------



## CMTFR

CitizenM said:


> Update, and I couldn't edit my original post for some reason.
> 
> I wanted to specify that I was wrong about the white gold on the movement. It turns out that, at least in regard to the rotor, it's rhodium plated tungsten. As far as I know, only the hands and indices are solid white gold (also rhodium plated). I misread the Watchtime article (reading about the 8501, which DOES use a solid gold rotor, but not white gold).


 Thanks for the update, CitizenM. 
Actually, I found "the white gold on the movement" a little strange; just imagine the weight and the final price Omega would have to charge for it. 
But that was only a small lapsus that certainly doesn't overshadows all the exhaustive and generous work you've been sharing with us all. 
Thank you
Regards
C.


----------



## CitizenM

CMTFR said:


> Thanks for the update, CitizenM.
> Actually, I found "the white gold on the movement" a little strange; just imagine the weight and the final price Omega would have to charge for it.
> But that was only a small lapsus that certainly doesn't overshadows all the exhaustive and generous work you've been sharing with us all.
> Thank you
> Regards
> C.


Yeah, it's my fault. I was reading the Watchtime article about the watch and read that it had a gold rotor etc. But I didn't notice I was reading a little note on the 8501, the yellow gold variety, and not the 8500. Too bad. But the movement still LOOKS like white gold, which is great. Very "pure" looking.

On another down note, the +1/week accuracy lasted two-three weeks (hard to say exactly) but it's back to +1/day for some reason. No clue what changed.


----------



## bydandie

A stunning review, thanks!  I bought the AT8500 second hand recently but didn't really appreciate the movement as much as I should've as the price was such that it would've gone with too much reading!

The Si-14 would've been nice, but the difference in price would've been too much and it's simply more bragging rights IMHO compared to the other features in the movement.

The dial is the equal of my other watches with 'character dials', the Sinn 203 Arktis and the Alt1-C, with the look and dial changing dependant on the angle the light hits it. The complete package is stunning with mix of brushed and polished surfaces really making the watch, as the photo's below hopefully show.


----------



## Marts7

Sorry, been absent for a while.

It got to 56 hours without bleeding any time before I fell asleep. When I awoke, the watch had stopped at just over 60 hours (approximately 20 minutes over). In the two months since then I've noticed the watch has settled into a regimented +4 per day (no longer the +4.5). I don't think it's varying one iota. Impressive. In six hours it will be plus 1, twelve hours plus 2 etc... very, very stable.

I still wish it would run as tightly as my Aqua Timer though. That thing regularly does +5 over the course of a week! It does have more isochronism though (trade off I guess). I know this isn't an IWC thread, but that piece ran as much as +10 when I first got it and continued to settle for what seemed to be 6-12 months.


----------



## Anans1

Just want to say excellent review. Omega has come a long way in its quest to beat Rolex.


----------



## CitizenM

bydandie said:


> A stunning review, thanks!  I bought the AT8500 second hand recently but didn't really appreciate the movement as much as I should've as the price was such that it would've gone with too much reading!
> 
> The Si-14 would've been nice, but the difference in price would've been too much and it's simply more bragging rights IMHO compared to the other features in the movement.
> 
> The dial is the equal of my other watches with 'character dials', the Sinn 203 Arktis and the Alt1-C, with the look and dial changing dependant on the angle the light hits it. The complete package is stunning with mix of brushed and polished surfaces really making the watch, as the photo's below hopefully show.


Great photos! Don't worry about the SI-14. I've paid attention to the accuracy postings of people with and without, and as far as I can tell, there is no improvement at all. Maybe the difference will show up in a few years of ownership, but right now, no way you could know. And, besides, the hairspring used in these is basically the same material used in Breguet and IWC in house etc. Very nice stuff.


----------



## CitizenM

Marts7 said:


> Sorry, been absent for a while.
> 
> It got to 56 hours without bleeding any time before I fell asleep. When I awoke, the watch had stopped at just over 60 hours (approximately 20 minutes over). In the two months since then I've noticed the watch has settled into a regimented +4 per day (no longer the +4.5). I don't think it's varying one iota. Impressive. In six hours it will be plus 1, twelve hours plus 2 etc... very, very stable.
> 
> I still wish it would run as tightly as my Aqua Timer though. That thing regularly does +5 over the course of a week! It does have more isochronism though (trade off I guess). I know this isn't an IWC thread, but that piece ran as much as +10 when I first got it and continued to settle for what seemed to be 6-12 months.


There's always some luck of the draw with a new watch...but stability is the hallmark of a great movement.


----------



## Bo-CuL

CitizenM you are a true contributor to WUS. Thank you for the comprehensive review! :-!

I enjoyed reading through your review just as I am about to have a final exam on the AT 8500 materials. Such a great information on the 8500 caliber (especially the Si-14 spring balance) that makes me appreciate the movement even more. That debunked my presumption that the 8500 cal was merely a cosmetic improvement over the 2500 cal for Omega to step up their price point.


----------

