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Accuracy of the Chronomat B01 vs. Evolution
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Author:  Racerdj [ Sat Feb 16, 2013 5:57 am ]
Post subject:  Accuracy of the Chronomat B01 vs. Evolution
I have this month started a new rotation. I wear my new B01 every third day and my older evolution 2 days on and rest one day. Both watches stayed very close when I was switching every other day. I have noticed that the B01 stays close for the first 24 hours but will loose 5 seconds when it is in the 24-60 hour rest segment. With my engineering mind, it seems like the spring is not having the correct effect on time keeping when it approches the end of the reserve. I'm not a mechanical engineer however. Your thoughts?
Author:  Roffensian [ Sat Feb 16, 2013 8:13 am ]
Post subject:  Re: Accuracy of the Chronomat B01 vs. Evolution
When a mainspring winds down it will transmit less energy through the running train, and all other factors being equal the watch will gain time at the end of the power reserve because the reduced power reduces the amplitude of the balance spring and lower amplitude = higher frequency.

That said, 24 hours isn't anywhere near the end of the power reserve for an in house movement and there are many different factors at play in determining accuracy. Will the power reserve affect accuracy - sure, so will a number of other factors - the fact that the watch sits for an extended period without moving in a relatively stable temperature / humidity / etc for example.
Author:  Racerdj [ Sun Feb 17, 2013 5:24 am ]
Post subject:  Re: Accuracy of the Chronomat B01 vs. Evolution
An update: during the last 12 hours of reserve, my B01 lost 20 seconds. A little confusing since it has been stated that the watch should be running faster.
Author:  Roffensian [ Sun Feb 17, 2013 6:01 am ]
Post subject:  Re: Accuracy of the Chronomat B01 vs. Evolution
Racerdj wrote:
An update: during the last 12 hours of reserve, my B01 lost 20 seconds. A little confusing since it has been stated that the watch should be running faster.



Not what I said at all. I said "all other factors being equal" the watch will gain time. Clearly something else is going on that is affecting accuracy. That kind of error requires service attention and it could be any number of reasons. At a guess there is something causing friction in the running train and it is having more impact as the torque transmitted reduces.
Author:  Racerdj [ Sun Feb 17, 2013 6:36 am ]
Post subject:  Re: Accuracy of the Chronomat B01 vs. Evolution
Thanks for the clarification! When I was wearing the B01 everyday, it was gaining 1.5 to 2 seconds per day. Is service still required? I am in the final process of selecting a watch winder so this problem might not be an issue anymore.
Author:  Roffensian [ Sun Feb 17, 2013 6:50 am ]
Post subject:  Re: Accuracy of the Chronomat B01 vs. Evolution
Racerdj wrote:
Thanks for the clarification! When I was wearing the B01 everyday, it was gaining 1.5 to 2 seconds per day. Is service still required? I am in the final process of selecting a watch winder so this problem might not be an issue anymore.



If the watch is losing 20 seconds in 12 hours then it has an issue. Wearing it or putting it on a watchwinder is simply masking symptoms, not solving the problem. I've never found a watch that fixed itself!
Author:  Chronomat01LE [ Sun Feb 17, 2013 10:18 am ]
Post subject:  Re: Accuracy of the Chronomat B01 vs. Evolution
Racerdj wrote:
Thanks for the clarification! When I was wearing the B01 everyday, it was gaining 1.5 to 2 seconds per day. Is service still required? I am in the final process of selecting a watch winder so this problem might not be an issue anymore.



Yr case is definitely an issue which u must get it checked at the service centre. Whether u wear the watch daily or not as long as the time loss/gain doesn't run within COSC specs u should get it rectified. IMO either Amplitude is low(which can be caused by several factors)and requires servicing or needs regulation...Mine had been great since I got it back more than a mth ago. Was constantly losing 10 sec per day but after getting back it has been about 1 sec gain per day. The last time I wound my watch from fully stopped was about 3 weeks plus ago. There were some of the days in between which I didn't wear it. Till now it has only gained a total of 20 sec after wearing it for 20 over days. To me the accuracy is amazing so u should bother the service centre as much as u can until u get yr watch in tip-top condition...Do check yr chronograph and date functions before u send it in so that any issues u can get them to rectify them one shot.
Author:  Driver8 [ Mon Feb 18, 2013 3:26 am ]
Post subject:  Re: Accuracy of the Chronomat B01 vs. Evolution
Irregular gains/loses depending on how much power reserve is left (i.e. how wound the mainspring is) sounds like an isochronism issue too me. Breitling should be able to fix this for you.... although IWC failed to fix this on my old Big Pilot.
Author:  Racerdj [ Thu Feb 21, 2013 5:38 am ]
Post subject:  Re: Accuracy of the Chronomat B01 vs. Evolution
I have done several more tests and have found the time loss is in the last several hours of the 70 hour reserve cycle. The B01 stays in the +1 to 1.5 second gain oer day for at least 60 plus hours.
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