[6SpeedTA95]

If it's a link to an older thread or an article or something that would be great. Or if you know and can post them here that is great too. I thought there was a thread about that but I've searched on the forum and searched on google and can't really find anything that lines out the differences by version. Help would be appreciated...

 

[mazman01]

I'd like to know too. And if you don't mind, how the 8500 compares to them, and what specifically makes it better as everyone says. If not in this thread than another maybe, as to not hijack this one.

 

[6SpeedTA95]

I'd like to know too. And if you don't mind, how the 8500 compares to them, and what specifically makes it better as everyone says. If not in this thread than another maybe, as to not hijack this one.

Feel free to discuss that here. Just keep in mind theere is a 2500 vs 8500 thread already on the omega front page.

 

[Mystro]

On a side note. the Planet Ocean only has had the 2500C movement from its introduction. It has recently received the 2500D movement. Only time will tell what if any advantages or disadvantages the 2500D movement has over the 2500C.

 

[iinsic]

A lot was covered here: https://www.watchuseek.com/f20/will-2500d-end-reliability-issues-617533.html

 

[lvt]

The 2500's escapement is simple, fully functional, but Omega found that they could still make a better one

The D version's escapement is almost identical to the 8500's but without the Si14 balance wheel.

It's heavily modified and more complicated than the 2500 (B, C) escapement and would be capable of running at higher beat rate in the future like the 93xx (anyway it won't happen with the 2500D).

 

[M4tt]

Only the 2500 B, C and D are likely to be seen on WUS. The major differences between the three are:

The B revision had a beat rate of 28,800 and wouldn't always start from rest without a flick.

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.

I also do not believe any version of the 2500 apart from the A to be any less reliable than any equivalent movement. My reasons have been repeated so many times as to be easily found through search and so I will not bother rehearsing them here.

 

[lvt]

Good explanation, M4tt, as usual.

I also think that the 2500 is as reliable as a 2892 but the 2892 has a big advantage : its simplicity, and in mechanical stuffs simplicity means more reliability.

The 2500D/8500 escapement is even more complicated than the previous 2500 with added parts so I still ignore how the Co-ax would last longer than a Swiss lever which is 10 times simpler, escecially when the next generation of the Co-ax will all run in 28,800bph.

At least one thing for sure now is that the 3-tier escapement seems to have a better handling of the power flow so the stoppage and the flick-to-start could be avoided.

 

[iinsic]

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.

So how does changing the escape wheel in the repairs of nonworking 2500Cs resolve whatever underlying problem exists with the unmodified movement? What has Omega figured out about the 2500C that they think will be fixed by this switch?

 

[Dixan]

The 2500D/8500 escapement is even more complicated than the previous 2500 with added parts so I still ignore how the Co-ax would last longer than a Swiss lever which is 10 times simpler, escecially when the next generation of the Co-ax will all run in 28,800bph.

Dude, you have to stop putting out this bad information. Did I miss something, here? Unless something happened since the last time you made this same irresponsible, purely speculative statement, and Omega has since officially announced that the next generation of Co-Axial movements will again beat at a faster beat rate, then your statement once again comes across as nothing more than your wish, stated as fact. Please stop stating things you personally wish to see happen as factual, or otherwise officially planned. :roll:

EDIT: IDK, maybe word your statements in a way that conveys your desire for Omega to bring future Co-Axial movement beat rates back up, but doesn't necessarily (mis)state that that will happen for sure, or is in any way officially planned by Omega. You might not even be alone in wishing that would happen. I personally don't see it happening, but I guess we'll just have to see.

 

[M4tt]

I also think that the 2500 is as reliable as a 2892 but the 2892 has a big advantage : its simplicity, and in mechanical stuffs simplicity means more reliability.

So, just to be clear, you are saying that they are both as reliable but the 2892 is more reliable because it is simpler?

Personally I think that simplicity is not obviously the key reason that something is reliable. Good, well executed design in high quality materials is usually the reason that something is reliable. Take a Russian Lada car engine. These are astonishingly simple and, in my experience, often have a total of no moving parts. A Mercedes engine is significantly more complex and yet manages to be infinitely more reliable. Likewise, a quartz watch is a far more complex design than a mechanical (if a little more inscrutable) and yet...

As for the changes between the 2500C and the 2500D...

The 2500D/8500 escapement is even more complicated than the previous 2500 with added parts so I still ignore how the Co-ax would last longer than a Swiss lever which is 10 times simpler, escecially when the next generation of the Co-ax will all run in 28,800bph.

I'm not sure how the splitting of the functions of one quite complex wheel into two far simpler wheels with a single function each adds much to the complexity of the escapement. Personally I'd say that this simplifies it. More to the point, I'm not clear what the added parts are. Perhaps a list would be helpful as I can't think of any added parts and there doesn't seem to be much of a change in the parts count.

The 2500D/8500 escapement is even more complicated than the previous 2500 with added parts so I still ignore how the Co-ax would last longer than a Swiss lever which is 10 times simpler, escecially when the next generation of the Co-ax will all run in 28,800bph.

I don't think it is more complicated and I certainly don't think that the coaxial is 'ten times' more complicated. A little bit more complicated sure, but mostly it's just different. I have explained how this difference makes the watch more stable elsewhere.

At least one thing for sure now is that the 3-tier escapement seems to have a better handling of the power flow so the stoppage and the flick-to-start could be avoided.

The need to put a little energy in the system to start isn't a fault in the first place, but it was 'solved' with the C revision. The 'stoppages', which now seem to be accepted as a reality, are still only evidenced by less than fifty complaints over a three year period on WUS. As several million 2500 movements were made in that period and WUS is around the top of google for this search term (and the majority of complaints came from new members) I'd say we are looking at a clear case of sample bias giving a misleading impression. (But I've said this all before).

Omega say that they moved the 2500 to a three tier coaxial wheel to standardise the escapement between the 2500 and 8500. However, as I have hypothesised elsewhere (and we have argued to death previously) there seems to be a possibility that oil may migrate from the leading edge of the pinion of the coaxial wheel (which powers the escapement) to the trailing edge (which takes power from the intermediate wheel) and cause an issue. This would explain why Omega are so precise about the amount of oil used and the application of an epilame. In the 2500D the potential issue with oil migration is solved as the trailing edge of the pinion wheel has no function as power is delivered through an ordinary cog elsewhere on the coaxial wheel. This cog would not be terribly sensitive to oil migration even if the oil migrated that much further, which seems unlikely. In short, I'm not sure there is an issue with the coaxial escapement of the sort imagined by those who are not statistically minded, but if there were and if this were the problem, then it is solved.

However, in my experience,any fault at all, from a magnetised hairspring to needing a service seems to have been included in the '2500 problem' - there seem to be a very small number of watches for whom oil migration may have been a problem and an awful lot of people who joined WUS Omega to vent and left again. There is nothing wrong with doing this, but when added to the usual issues any movement will have it has given the 2500C an unfairly poor reputation. As far as I am aware there have been no complaints about the 2500B on WUS and less than ten about the 2500C in any other watch than the Planet Ocean.

 

[M4tt]

So how does changing the escape wheel in the repairs of nonworking 2500Cs resolve whatever underlying problem exists with the unmodified movement?

I don't believe that Omega modify the 2500C while performing repairs. I may be wrong, but I don't remember seeing any significant evidence of this

What has Omega figured out about the 2500C that they think will be fixed by this switch?

I guess I answered this above. However, given that the 2500C has been one of Omega's most successful movements, in terms of sales, since the sixties adn they didn't change it for many years I'd guess that they didn't really think there was a problem, but have just been upgrading in the light of experience from the 8500 (which was a larger movement) To assume that an upgrade is automatically a response to a fault, rather than a natural process that is part of the life of any artifact manufactured over a long period seems odd. There were twenty four marks of Spitfire for example; this does not mean that the MKII which equipped the RAF during the Battle of Britain was a profoundly flawed aircraft, merely that as the state of the art moved forward the aircraft was updated to reflect this.

 

[6SpeedTA95]

I don't believe that Omega modify the 2500C while performing repairs. I may be wrong, but I don't remember seeing any significant evidence of this

I guess I answered this above. However, given that the 2500C has been one of Omega's most successful movements, in terms of sales, since the sixties adn they didn't change it for many years I'd guess that they didn't really think there was a problem, but have just been upgrading in the light of experience from the 8500 (which was a larger movement) To assume that an upgrade is automatically a response to a fault, rather than a natural process that is part of the life of any artifact manufactured over a long period seems odd. There were twenty four marks of Spitfire for example; this does not mean that the MKII which equipped the RAF during the Battle of Britain was a profoundly flawed aircraft, merely that as the state of the art moved forward the aircraft was updated to reflect this.

What? I thought the 2500C made its debut in the PO and the first 2500 was put into mainstream production in 1999...not in the 1960s...

 

[iinsic]

I don't believe that Omega modify the 2500C while performing repairs. I may be wrong, but I don't remember seeing any significant evidence of this

I guess, since Al at Archer Watches was the one who told me about the new escape wheel in the repaired 2500Cs, I should have just asked him why Omega does that. :roll:

 

[Zidane]

What? I thought the 2500C made its debut in the PO and the first 2500 was put into mainstream production in 1999...not in the 1960s...

He's saying the movement is one of the most successful movements, in terms of sales, since the sixties; not that it was actually sold in the sixties.

 

[Archer]

So how does changing the escape wheel in the repairs of nonworking 2500Cs resolve whatever underlying problem exists with the unmodified movement? What has Omega figured out about the 2500C that they think will be fixed by this switch?

The technical guide for the 2500 doesn't give a lot of detail, but based on what I see there the change of the intermediate escape wheel is designed to eliminate a black residue forming that can cause low amplitude and stopping of the watch. The new wheel apparently has a different surface treatment.

Hope this helps.

Cheers, Al

 

[iinsic]

I don't believe that Omega modify the 2500C while performing repairs. I may be wrong, but I don't remember seeing any significant evidence of this

The technical guide for the 2500 doesn't give a lot of detail, but based on what I see there the change of the intermediate escape wheel is designed to eliminate a black residue forming that can cause low amplitude and stopping of the watch. The new wheel apparently has a different surface treatment.

Hope this helps.

Cheers, Al

Thank you, Al, for that clarification! :-!

 

[Undersköterskan]

Excellent posts, M4tt !

 

[lvt]

Dude, you have to stop putting out this bad information. Did I miss something, here? Unless something happened since the last time you made this same irresponsible, purely speculative statement, and Omega has since officially announced that the next generation of Co-Axial movements will again beat at a faster beat rate, then your statement once again comes across as nothing more than your wish, stated as fact. Please stop stating things you personally wish to see happen as factual, or otherwise officially planned. :roll:

EDIT: IDK, maybe word your statements in a way that conveys your desire for Omega to bring future Co-Axial movement beat rates back up, but doesn't necessarily (mis)state that that will happen for sure, or is in any way officially planned by Omega. You might not even be alone in wishing that would happen. I personally don't see it happening, but I guess we'll just have to see.

The 9300 caliber's escapement is nothing other than a modified version of the 8500's escapement and it beats at 28,800bph, so Omega actually mastered the Co-ax technology, adding a third wheel to the double escape wheel is a bit strange but apparently it works, should we call it Triple-ax instead of Co-ax ?

It's not my irresponsible statement but it's a reality, Omega always wanted to have a new escapement beating at the industry standard beat rate, if you make less than 1,000 watches per year, you are probably a very high-end brand and you can have your watches running at 21,600bph or even lower, it doesn't matter as you actually sell 45K watches, but when you want to sell hundreds thousands watches per year at lower price tags you are a major player on the field and you have to follow the standard before you can set a standard for others, in the case of Omega you'd better try to reach the standard 28,800bph rather than try to create a standard 25,200bph because noone would follow you.

 

[drunken monkey]

but it is just supposition on your part.
it may be based on observations and it may actually be the case but unless it is confirmed by Omega that it is a firm company plan/policy/target, it is still just supposition.