Haven`t had my hands on an Omega Seamaster Pro for a good few months, my own 2 have been in storage not getting worn. That changed a couple of weeks back and I`ve ended up with 4 on the bench and surrounding area!
The bi-metal is my own, dating from 2004, I dug it out recently to wear for a few days. At the same time the architect who did the design work on my extension passed me his 007 limited edition watch to sort out, a watch that's had a hard life and needed attention. I also took a 2531.80 in for service. The 4th one is a black Bond co-axial dating from 2009 which I`ve owned for several years and worn sparingly. Having never worked on an Omega co-axial I decided it was time that changed so I serviced the black Bond. It was interesting to see dried up lubricant on the co-axial wheel, in places where it shouldn't be, so the trace of lubricant originally applied had obviously spread or maybe was over-oiled from new. Despite this the watch was still running, but it's running far better after a full stripdown. The only daunting aspect of servicing this 2500C is the oiling of the co-axial wheel, it requires a microscope to check and a very steady hand to apply, it took me 2 goes to get a satisfactory result. Removing and replacing the balance requires a different technique from normal and care must be taken to avoid damaging anything.
The 007 Ltd edition watch has the same 2500c movement, I'd assumed it was the older cal 1120 when I agreed to sort it out but having serviced my own I was happy to tackle it. That's now running nicely and it'll be back with the owner soon, I owed the guy a favour for helping my stepdaughter resolve some issues recently with building work that didn`t go well.
The Bond 2531.80, with the cal 1120 movement, was straightforward to service, it's identical to the 2500C co-axial apart from the escapement parts and 2 of the train wheels to accommodate the lower beat rate. These movements are a joy to work on, an excellent design in my view.
I`ve aired my views on the co-axial development many times, suffice to say I'm not a fan and having now worked on one I haven`t changed my opinion. Positional agreement is no better than the 1120, the co-axial is tricky to regulate (special tool and a very steady hand required) and if that's done wrongly the poise of the balance will be spoiled. It's a clever piece of design and it does reduce the friction in the escapement compared to a conventional lever design, but I think the claim for a longer service interval was far-fetched. I also think the design is less tolerant to wear in the longer term. The free-sprung balance that goes with the design is OK, I like that even though the regulation (Rolex style) with screws on the balance rim is a pain, upgrading the 1120 in this manner without the co-axial escapement would've made more sense.
The marketing potential of the co-axial has been exploited to the full, the later cal 8500 movement has much to praise it, but don't be fooled into thinking the co-axial escapement improves the performance to any extent. It's a v. interesting design but a pointless development in my view. Omega deserve credit for making it work and sticking with it after the early versions had issues, the changes introduced during production of the 2500 makes interesting reading and it would've been easier to allow it to quietly die.
Its been interesting to have 4 pre-ceramic SMPs around at the same time. The co-axials have a slightly deeper caseback (0.8mm) for reasons that aren`t obvious other than the logo change. The skeleton hands are slightly longer compared to the 2531.80, which together with the applied Omega logo looks a bit better. I prefer the black Bond to the blue, the 007 version does nothing for me at all with the silly seconds hand design and swirly dial. My own bimetal model is a bit left-field and will split opinions, it's a rare one and I like it, I also have the original blue dial for it but prefer the black, which is identical to the 2254.50.
One minor difference between versions is the height of the hands, on the co-axials the hr hand sits higher above the dial. As the dial side needed no redesign I assume this is to give more clearance over the applied logo. It also means the cannon pinion and hr wheel and centre seconds wheel are specific to the 2500C. I recall fitting the Americas cup-style dial, with applied logo and indices, to a couple of 2254.50s in the past, it was a popular mod, and I remember the clearance for the hands was tight!
There are other watches I prefer, I`m not really a dive watch fan, but I like the pre-ceramic SMPs. Far nicer than the later versions in my view and certainly far more affordable back in the day!
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