The Dive Watch Connection

So I've decided to get another 42mm PO and as awesome as the 8500 is, I may just get another PO 2500. I plan to move a few micros/cheapos to (partially) fund it.
I am looking for a D if I go the 2500 route. However some C have been upgraded during service. My question is what was the issue on the C and what are the differences?
Can one confirm a C was upgraded or must rely on seller's word?

Thanks. B

The difference between the C and the D deal with the coaxial escapement, and the problem was intermittent stopping. Here's a decent summary of the differences:

Some Wussy wrote: The C revision had a beat rate of 25,200 which put a little more torque into the escapement for the same strength of spring. This gave slightly lower wear, pretty well certain self starting and an extra four hours reserve for no significant loss of stability. In addition there were some minor changes to the shape of the lever, small variations in lift angle and so on.

The D revision split the coaxial wheel from two layers to three to separate the function of taking power from the intermediate wheel from the function of providing an impulse to the pallet. In the 2500C, the pinion wheel did both jobs. In the 2500D, the job of taking power from the intermediate wheel has been delegated to an ordinary cog. This leaves the pinion wheel free to do a single job well.

The C solution is the more elegant while the D solution simplifies the problem (powering the pinion wheel) to be solved. Which is the better solution is probably a matter of taste. Personally, I have two B revisions, which makes my opinion on the matter pretty clear.

The updated C is still a fundamentally different design, however I haven't heard of a "fixed C" experiencing the stopping. I went with a D because it was newer, "more rare", and worked correctly from the start FWIW.

brice i did the research on WUS and from what I gather a serviced C is still a good watch. But the D is the appropriate solution for what they set out to do with the movement initially.

so buy an orange numbered D and sell it to me next month. Thanks.

Ninja editing I see.

some how ORANGE came out to be PRANG ???

I've playing with an idea of 2500 vs 8500. As the prices are pretty much the same between C and D, D is no brainer.

The date aperture on the D's are slightly nicer, but the date font is better on the C - both tiny difference, but that's the sort of thing that drives this hobby.

The early iterations of the 2500, on rare occasion, just stopped intermittently. Back then no one was confident as to the cause (they may have figured it out by now). In the 20 or Omega 2500s my roommate had, only one of them seemed to have the problem, and that was on a pre-owned PO so it's not really possible to say that it was some fault of the movement (as opposed to past-life trauma). We had it overhauled and it worked great, the private watchmaker never did explain what the problem specifically was.

The D was a pretty major overhaul of the escapement and should avoid that problem, but honestly, the problems of the 2500s were always overblown. Given the crazy high volumes of that watch, the rare occasional complaint I caught on WUS indicated to me that it was actually a pretty reliable movement. The 2500 is still used by Omega today even.

Basically, the difference was the kind of co-axial escapement used. In the 2500C and prior, Omega used a simpler version that some call the "flat co-axial." In the 2500D, 8500 and 9300, the co-ax is a three level design. That's oversimplifying it but going into greater detail would exceed my technical expertise.

I can vouch for the issue. I bought an Omega AT brand new from an AD in 2010. had the 2500 movement. Damn thing would refuse to start from a dead stop a couple of times a month. Ended up getting rid of it.

DenverBuff wrote:I can vouch for the issue. I bought an Omega AT brand new from an AD in 2010 and the damn thing would refuse to start from a dead stop a couple of times a month. Ended up getting rid of it.

Same here

I've had every iteration of the PO and the only one I had issues with was a C. Nothing like a watch just stopping on you to make you say 'never again'


Your question, though, was with respect to C's that have been worked on, correct? If so, think about the question..are you willing to trust the 'fix'? I wouldn't take the chance

That said, the 2500 fit better for me.

BBK357 wrote:brice i did the research on WUS and from what I gather a serviced C is still a good watch. But the D is the appropriate solution for what they set out to do with the movement initially.

thanks.

deepcdvr wrote:

DenverBuff wrote:I can vouch for the issue. I bought an Omega AT brand new from an AD in 2010 and the damn thing would refuse to start from a dead stop a couple of times a month. Ended up getting rid of it.

Same here

I've had every iteration of the PO and the only one I had issues with was a C. Nothing like a watch just stopping on you to make you say 'never again'


Your question, though, was with respect to C's that have been worked on, correct? If so, think about the question..are you willing to trust the 'fix'? I wouldn't take the chance

That said, the 2500 fit better for me.

Yeah. 2500 C fixed.
I should have never sold my D

Panerai7 wrote:I've playing with an idea of 2500 vs 8500. As the prices are pretty much the same between C and D, D is no brainer.

Not so much a price issue as it is an availability issue for me on the D

I had a "C" stop after about 18 months, but it was fixed under warranty. I also had a stoppage with a "D" movement, so I say they're equal.

I recall Al Archer posting something about a different escapement wheel (?) and different oil, which makes it less likely to gum up.

The "D" has a completely different three-level escapement, to minimize stress and maximize efficiency.

I'm not a professional watch nerd, only an amateur, so take what I say with a grain of salt peter.

I had a C, and also suffered the stoppage issue. As others have said, it seems that after they are fixed they are good.

I recall reading a thread on wussy Omega forum about the actual work carried out to fix the issue from a watchmakers perspective but it was a long time ago. If I can find it I will post it up.

I have sold the watch but I miss my PO a bit actually

I've had two C's stop on me.

My "C " was fixed in 2011 and I subsequently gave it to my Dad. It's been fine since.

Get the 8500

andrema wrote:Get the 8500

Had the 8500 and although the dial and bezel are nice, I found it too tall and top heavy, much less comfortable

I have both. I guess the "D" variant is better on paper due to the escapement being three tiers. Certainly more rare if that matters to you.

When I was looking for a PO I had the option of an 8500 or a BNIB 'D` that my AD still had in stock. I went with the' D' because I preferred the case dimensions and the dial and bezel designs. I have no regrets, the watch has run flawlessly (hmm maybe I shouldn't have said that ) and has turned out to be one of my favorite watches.

I'd go with the 'D' .

The 2500 also has more design cues from the old school SM300, which I prefer.

Jeep99dad wrote:

andrema wrote:Get the 8500

Had the 8500 and although the dial and bezel are nice, I found it too tall and top heavy, much less comfortable

Ditto.

But I just went back and looked at my pics and kinda want one back again. Sickness.