Sub 41 Accuracy Question

[prk154]

I've had my new sub for about a month now. I set it immediately based on the atomic clock and have worn it every day since. For the first couple weeks, it consistently lost about one second per day...which is great by my standards.

The interesting thing is that it has been gaining back time for the last two weeks...to the point where it is almost back to being dead-on accurate with the atomic clock.

Is it normal for a watch to lose and then reverse to begin gaining time...or vice versa? I was always under the impression that it would only move in one direction.

[Robert Bruce]

In my experience it is normal for a mechanical watch to drift in its timing over the first few months. The reason it's noticeable on your Sub is that it's so close to keeping perfect time. If it were off by 5 seconds a day and it drifted to 6 seconds off, it would be negligible. I have an Omega Planet Ocean that started out a second a day fast, and slowed over the first year to a second a day slow, and in the second year it drifted back to now a second a day fast again. Again, only noticeable because it is so crazy close to begin with.

[Mr. K]

I think it is very normal during the break-in period.

[stark1]

Agree with above posts. I'd also add that resting position at night is important (assuming you don't wear your watch to sleep). For instance, my sub (3130 movement) keeps perfect time dial down when resting, but +1 or so if dial up. If you get a clear sense of your watch's timekeeping at each position, you'll be able to moderate it for it to keep perfect time.

[travisb]

Definitely. I've experienced the same. My 32xx movements are nearly spot on.
Impressive accuracy.

[padi56]

Originally Posted by prk154

I've had my new sub for about a month now. I set it immediately based on the atomic clock and have worn it every day since. For the first couple weeks, it consistently lost about one second per day...which is great by my standards.

The interesting thing is that it has been gaining back time for the last two weeks...to the point where it is almost back to being dead-on accurate with the atomic clock.

Is it normal for a watch to lose and then reverse to begin gaining time...or vice versa? I was always under the impression that it would only move in one direction.

No purely mechanical watch will not keep 100% perfect time no matter the brand or cost.Many things affect mechanical watches on the wrist,such as gravity,mainspring power-reserve,metal expansion and contraction, temperature variations, subtle changes in lubrication and friction, shocks, and so on.Your watch is running fine just enjoy wearing it in good health thats the most important.

[Rori]

Originally Posted by stark1

Agree with above posts. I'd also add that resting position at night is important (assuming you don't wear your watch to sleep). For instance, my sub (3130 movement) keeps perfect time dial down when resting, but +1 or so if dial up. If you get a clear sense of your watch's timekeeping at each position, you'll be able to moderate it for it to keep perfect time.

I started regulating my watches only lately but resting them on the right side during nighttime. My Tudor runs about 1.5 sec a day fast, putting it crown down during the night brings it back to almost +0 -0 the day after.
My SD43 started 2 sec fast when new, now it's 0.5 slow, I regulate it by resting it dial dow during night, it runs faster this way than when dial up.
Learning this regulation tips is so amazing.

[Fred48]

Amazing, perhaps, but not unusual. The accuracy of a mechanical watch will vary with different positions. That's why COSC tests them over five positions (+ temperature), and takes an average. To pass, they must meet limits of average accuracy and positional variation.
Unlike a quartz watch where accuracy is essentially fixed, the nice thing about a mechanical watch is that you can do self regulation by positional change, as you have found out.

[Meyrin]

It sounds like your Sub is running damn accurately! Nothing wrong here, a slight drift is perfectly normal imho! If you want anything more accurate you'll have to buy a quartz watch...but a decent one! Wear it and enjoy it, it´s a great watch!