Activity on accuracy

[Ck8]

My GMT IIc gains 3-4 secs after 8 hours wear at work. I sit behind a desk and the hardest activity is probably picking up the phone. When I am not wearing it does not gain or loose sometimes gaining 1 sec overnight, which is strange as at rest it is quite accurate.
I rang the RSC and they say that is within COSC and depends on how active the wearer is. I don't think that is right gaining 4 secs in 8 hours which if I wear it 24/7 would equate to 12 secs. I do not wear my watch for anything strenuous or sporting activities.

Does anyone find accuracy is affected by their activity? Can any explain why my watch gains when I am wearing it, even though I am not very active.

[padi56]

Originally Posted by Ck8

My GMT IIc gains 3-4 secs after 8 hours wear at work. I sit behind a desk and the hardest activity is probably picking up the phone. When I am not wearing it does not gain or loose sometimes gaining 1 sec overnight, which is strange as at rest it is quite accurate.
I rang the RSC and they say that is within COSC and depends on how active the wearer is. I don't think that is right gaining 4 secs in 8 hours which if I wear it 24/7 would equate to 12 secs. I do not wear my watch for anything strenuous or sporting activities.

Does anyone find accuracy is affected by their activity? Can any explain why my watch gains when I am wearing it, even though I am not very active.

Gravity affects mechanical watches the most thats why they are tested in 5 different positions.And in those different positions there will be slight deviations in the timekeeping.But don't worry over a few seconds in 8 or so hours you cannot test any watch like that.Remember this the escapement of a mechanical watch in 24 hours pushes the gears 432,000 times. Since a day has 86,400 seconds, even a watch that runs five minutes fast or slow each day has an accuracy of over 99.6 percent! A finer mechanical watch that gains or loses about six to nine seconds a day or about a minute a week has a breathtaking precision of over 99.99 per cent. This is very high precision, given the fact that the movement is constantly affected by the earth's gravity, metal expansion and contraction, temperature variations, subtle changes in lubrication and friction, shocks, and so on.The fact is that no mechanical watch made will keep perfect time, very close yes but perfect no.The COSC spec is a average of -4 to +6 over 24 hours..So most Rolex are 99.994% accurate what more could anyone ask from a mechanical watch.Have you ever given your watch a full manual wind say 40 full crown turn clock wise.?Because when wearing with low activity you are not winding your watch enough that could have a effect on over all timekeeping.

[acce1999]

Originally Posted by Ck8

My GMT IIc gains 3-4 secs after 8 hours wear at work. I sit behind a desk and the hardest activity is probably picking up the phone. When I am not wearing it does not gain or loose sometimes gaining 1 sec overnight, which is strange as at rest it is quite accurate.
I rang the RSC and they say that is within COSC and depends on how active the wearer is. I don't think that is right gaining 4 secs in 8 hours which if I wear it 24/7 would equate to 12 secs. I do not wear my watch for anything strenuous or sporting activities.

Does anyone find accuracy is affected by their activity? Can any explain why my watch gains when I am wearing it, even though I am not very active.

Yes, your accuracy depends very much on activity. It is more about the main spring tension than the position of the watch, and that is why Rolex have been using the bi-directional rotor winding mechanism, to offer maximum tension.

The watch performance is best when the main spring offers optimum tension, and torque to the balance spring.

I've noticed that on all my watches the accuracy deteriorates quite dramatically when the spring operates on the last hours of power reserve.

All my watches are dead accurate when they have full power, like when newly wound or when I am very active (in sports for example). But just a couple of hours later with no or low activity they start to drift in accuracy.

Try this (as an experiment): Give your watch 40 full winds to ensure full tension, then wear the watch whilst doing something that keeps you active (to maintain full power), and then check the accuracy.

Also. COSC is an average of -4 to +6 seconds per day over a period of 15 days, including different positions and temperatures. During the test the watch is fully wound once per 24h. A watch can loose or gain as much as 15 seconds one single day of those, and still deliver within the average of -4 to +6.

Best,

A

[Ck8]

Originally Posted by acce1999

Yes, your accuracy depends very much on activity. It is more about the main spring tension than the position of the watch, and that is why Rolex have been using the bi-directional rotor winding mechanism, to offer maximum tension.

The watch performance is best when the main spring offers optimum tension, and torque to the balance spring.

I've noticed that on all my watches the accuracy deteriorates quite dramatically when the spring operates on the last hours of power reserve.

All my watches are dead accurate when they have full power, like when newly wound or when I am very active (in sports for example). But just a couple of hours later with no or low activity they start to drift in accuracy.

Try this (as an experiment): Give your watch 40 full winds to ensure full tension, then wear the watch whilst doing something that keeps you active (to maintain full power), and then check the accuracy.

Also. COSC is an average of -4 to +6 seconds per day over a period of 15 days, including different positions and temperatures. During the test the watch is fully wound once per 24h. A watch can loose or gain as much as 15 seconds one single day of those, and still deliver within the average of -4 to +6.

Best,

A

Yes did that today with more than 40 winds and wore the same way I always have been and there is no change. It gained 4 secs in 8 hours wear.

Anyone know how long it takes a new watch to bed in before I should consider sending back for regulating.

[Kapture1]

Its better than being 4-8 sec slow. At least you can pull the crown for 4-8 seconds and screw it back down.

[DDG]

I've never had a Rolex that kept good time. They look good, but really are a lousey timekeeper. The ones I've owned always ran fast. You have to get a cheap digital or look at your cell phone for correct time.