Does my SMPc use a 2500c or 2005d movement?

Hi LeDave,

Well you heard wrong. The first 2500 did not have a letter after it - it became the A revision when the B was released. Then the C, and finally the D. The A, B, and C have all had problems, which is why there is a D revision - if it was working well why would they make all these revisions?

None of Omegas designs exactly match what George Daniels designed, but the big difference between the C and the D is that the C is a 2 level design, and the D is a 3 level design. Actually the A, B, and C are all 2 levels designs, and these are the most problematic.

Both the 2 and 3 level designs were initially thought up by George Daniels, not Omega. In fact the "new" 3 level design is the original co-axial design. The 2 level was made by Daniels when some brands he tried to sell the co-axial to said it was too thick, so he redesigned it to the 2 level to save vertical space.

The 2500D is less prone to problems, so maybe that is where you heard it requires less maintenance. As someone pointed out, Omega claims an increased service interval with these co-axial watches, but I personally have some issues with that. Even discounting the problem movements, the escapement is just one part of a whole system inside a watch that needs attention periodically. When I get a watch in that has stopped, it's the whole movement that needs service, not just the escapement. Usually it has stopped because all the oils in the train wheels have dried up and caused the watch to bog down and stop.

So the idea that creating less friction in one specific place (even an important one like the escapement) will magically make the service interval increase by orders of magnitude is not really true. It may increase the interval slightly, but over the years Omega has backed down considerably from their initial claims.

With regards to the beat rate, versions A and B are 28,8000, and version C and D are 25,2000.

If you want to know what movement is in your watch, PM me the full serial number and I'll look it up for you.

Cheers, Al

Hello - I have posted this information on other forums, and possibly even here somewhere, but I'll do it again quickly...

The 2 level co-axial escapement has an inherent design problem, which stems from the dual role of the upper co-axial wheel teeth, and the intermediate escape wheel teeth. These teeth are designed to fill 2 purposes, and the shape required for the teeth to do this causes a build up of sticky residue on these teeth, which eventually causes what is widely known on forums as "the stopping problem."



This problem exists on all 2 level co-axial designs so the 2500 A, B, and C, and others like the early versions of the 3313, etc.

Omega attempted to remedy this problem several times with different solutions, and their first attempts were not successful. In the end the procedures for the application of epilame to the co-axial wheel and intermediate escape wheel were changed, and also a specific lubricant is applied to all 20 teeth of the intermediate escape wheel, and it is applied in a fairly substantial amount (at one time these teeth were left dry). In addition on the 2500C, there is a new intermediate escape wheel used with a different surface finish, but since Omega does not offer a similar new wheel for the other versions, the real need for this new wheel is somewhat suspect in my mind. But as they require, when I service a 2500C that has this residue (most of the co-axials I see do, even if they have not yet stopped because of it) I always replace the wheel - it's only $20 or so and worth doing if it helps prevent this problem from coming back.

To the best of my knowledge, this last fix that Omega has implemented has mitigated the problem, at least to a point where the build up of this residue is not causing the watches to come in for service prematurely. But the inherent design issue, the shape of those teeth, is still there. If someone bought a watch late in the production of the 2500C, then this new procedure would have been implemented at the factory, so in those cases it's no surprise that watches have run for a few years without stopping. It does not mean that they won't have this problem eventually, but it may not cause the watch to stop before it needs service for other reasons.

To me the fact that all current Omega co-axials are the 3 level design, which completely eliminates this problem, tells me that Omega thinks the 3 level is a more robust design and has less potential to cause them warranty problems. The fact that the 2 level design has been eliminated completely from their offerings tells me they are not 100% confident that they have completely solved the issues.

Hope this helps.

Cheers, Al

Some quick answers to a few posts:

1 - Once serviced with the new procedures, the watches do seem to run okay, but this was all implemented in about 2010, so now at 2014 we still a ways away from the time when some of these watches will be coming up for service. So far so good I guess. If you really want a piece that uses the 2500 C, then go for it.

2 - My wife would seriously disagree that I know everything, but thanks for the vote of confidence anyway.

3 - I believe the 8500 was released in 2007? Don't quote me on that but it seems it was in the works for a while. I can't say if it was designed as a replacement for the 2500 - but the 2500 is still being used in the SMPc with the 2500D version is used. I think the mods to the 2500 versions were to stop the warranty claims Omega was having. The A version had to have the bridge for the pallet fork and co-axial wheel beefed up (shock would cause the escapement to lock up), so that was the B version. Then they decided Daniels might be right that the beat rate needed to be lower, so the C version came out (this was said to improve the self starting capabilities of the movement, so when you wound it up it would start like a Swiss lever escapement would). By then they were getting the residue, so they finally went to the 3 level in the D.

Cheers, Al

Al, as always you're a fount of info! Was wondering - have you ever thought of compiling some of the common Omega questions (like this one about co-axial movements) or other technical questions into a series of FAQs on your website?

It might function like Desmond's Constellation reference guide - future forum members can be pointed to your FAQ much the same way we guide people to Desmond's blog, and it would save you typing the answers every few months on various forums. Plus it would be a huge treasure trove of info!

I've checked the serial number and it's a D version.

Cheers, Al