I’m looking at a pre owned Full Set 2201.50 with a 818439XX serial which should put the date around 2007 according to the charts. On the warranty card it says 2500 movement, but which 2500 would the watch most likely have judging by that serial ??? Ty.

 

My 81792XXX would also like to know. I've been assuming 2500C.

 

I believe a watchmaker with access to Omega’s db will be able to look up the SN and tell you which 2500 variant is under the hood.. @Archer ?

 

It will be a C, too early for the 'D'. Pretty sure the PO never had the 'B'. My 2008 is a 'C'

 

C or D only in the PO's

 

Look at the date font. Left, 2500C. Right, 2500D.

 

Not reliable - date indicators can easily be swapped.

 

Better than guessing without opening the caseback, though

 

Is it? I suppose it depends on how you see and value the D version. If it is priced at a premium over the C, then you could be paying extra for a version that you aren't really getting.

I've seen this date wheel thing thrown around forums for years now as well as serial number ranges as "proof" of what version you have. All I'm saying is, it's not reliable. If people want to rely on it, that's up to them, but I've personally had people ask me to swap their C date indicators out with the D versions (I declined to do so, but that doesn't mean every watchmaker will), so IMO this is not a completely theoretical situation.

 

My 8185xxxxx has a 2500c. If it is all original it should have a 2500c

 

@Archer

>I've personally had people ask me to swap their C date indicators out with the D versions

Really? God damn. Collecting is a minefield.

 

Thank you for everyone’s replies, judging by that C & D date wheel pic (considering the watch has the original date wheel) it looks like the watch I’m looking to purchase from a private seller is a C. I’m attaching 2 close up pics being I’m new w the Planet Ocean line. A good Omega watch buddy on here gave me a thumbs up on it from viewing the pics.

 

Honestly c vs d is not an issue to me if your going to wear it. The first gen 42mm white numeral PO is a classic.

 

My high 84m serial 2201 still had the C spec so leaving aside Al’s comment that both are seen, I would suggest that both 81m watches mentioned above are likely to have the C spec. The D was only seen pretty late in the life of the 2201. Like 2011-13 from what I recall. C can’t be converted to D without a full movement swap so I would suggest if your watch is earlier than 85m you have C.

The 3313 coax movement watches can be converted. My B became a C when it was serviced by Omega, despite them saying up front that they don’t swap the escapements any more. They clearly do.

 

Based on the sheer number of questions related to determining if these have the C or D, it is apparently a consideration for many. It would be for me if I was buying one, as the D eliminates the whole 2 level co-axial issue completely. As padders has mentioned the swap to the D was made late in the series, so there are definitely fewer of them out there.

 

Is there a rash of SMP failures out there I’m not aware of?

obviously the D is preferred and carries a premium, I’m just saying is the C that scary to own?

 

The bottom line is that the 2-level co-axial escapements are a fundamentally flawed design. When I did the co-axial training at Omega, it was acknowledged and they were struggling with ways to mitigate what became known as "the stopping problem" on various forums. This is where many of these watches would simply stop running, well before the warranty was even up (2 years at that time) and certainly well before what would be considered a normal service interval.

It wasn't every watch, but the numbers back in the day were significant enough that we spent a lot of time covering this topic at the training.

The problem has been covered in a lot of detail many times in many places by me and others, but in a nutshell the shape of the teeth on the intermediate co-axial wheel and the co-axial wheel were a compromise that made them have two functions, and this was done to the make the movement as thin as possible. The action of these teeth created a black sticky residue, that would gum up the escapement and cause it to stop - here's one example:



Here's a photo I took at the Omega training that shows the residue on the intermediate escape wheel displayed on a screen from a camera in a microscope they used for training:



Omega tried many things to solve this problem, and most of those things didn't work. In the end they even made a new intermediate escape wheel for the 2500C's only that had a different finish, and implemented new epilame and lubrication regimes. They didn't make new intermediate escape wheels for the 2500 A or B, because in the end the new epilame and lubrication were enough to make the problem go away to an extent that most owners would get pretty much a normal service interval out of the watch. But the build up doesn't go away.

The real solution is going back to the original design, which is the 3-level co-axial escapement. I'm sure there are plenty of people who will pipe in and say that they never had issues with their 2-level co-axials, but I can tell you that virtually every one I serviced had some of this residue building up on the teeth, so it was a matter of whether you had something else creep up before this issue did or not, whether you were affected by it.

There's a reason why none of Omega's current line up use the 2-level design. I suspect the reason they developed the kit to convert the 3313's was because they are simply much more labour intensive to service under warranty, so it was worth it to convert these, where it likely isn't with the 2500's.

"Scary" is not usually a term I use when it comes to watch ownership, but there's no question the 3-level designs are more reliable.

Cheers, Al