Science behind watch speeding up?

[makebread]

Hi all. Purchased a second-hand Tudor BB36 (9 months old) with ETA movement.

On delivery, it ran consistently around 3 seconds slow per 24 hours. That went on for about 3 weeks.

Then, randomly, it started running 0.5 seconds slow. Same conditions, nothing changed. It's been running consistently that way for about 2 weeks...

So what's the science behind this? I often here of watches "breaking in", but the general consensus is that they'll slow down, not speed up.

Perhaps I gave it a bang that's shifted something in the movement?

Sent from my SM-G981B using Tapatalk

[al503]

Same story with my DD40 that started slow and continued to slow down (apparent 32xx issue). It went into the safe when I got the SD43 as my daily. Took the DD40 out of the safe about a year later and it's running fast now...

[JCF81]

Magnetization?

[padi56]

Originally Posted by makebread

Hi all. Purchased a second-hand Tudor BB36 (9 months old) with ETA movement.

On delivery, it ran consistently around 3 seconds slow per 24 hours. That went on for about 3 weeks.

Then, randomly, it started running 0.5 seconds slow. Same conditions, nothing changed. It's been running consistently that way for about 2 weeks...

So what's the science behind this? I often here of watches "breaking in", but the general consensus is that they'll slow down, not speed up.

Perhaps I gave it a bang that's shifted something in the movement?

Sent from my SM-G981B using Tapatalk

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. Remember this the escapement of a mechanical watch in 24 hours pushes the gears 432,000 times and a day has 86,400 seconds. And on the wrist wearing or at rest the movement is always affected by mainspring power-reserve, 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 100% perfect time, very close yes but perfect no. And if you banged something in the movement, then you can be 100% sure you would not have the accuracy and consistency you have with your watch now.

[padi56]

Originally Posted by JCF81

Magnetization?

His watch is not magnetised in any way.

[makebread]

For added context, I wear my watch 24/7 (even to bed). I only take it off for a 15 min shower.

So resting dial up etc. is something I don't do.

I'm just curious why, all of sudden, this 9 month old watch decides to speed up. If it was new from an AD, say a few weeks old, then I'd understand.

But can it really "break in" 9 months later and run fast? Weird.

[Tools]

You could check your power reserve now that you have had some time to settle in to a wearing habit.

A watch in the lower half of it's power curve will run slightly faster than a watch in the upper end of the power curve.

It doesn't take much to affect the 86,000 plus seconds in every day. Even seasonal temperature changes can affect our watch timing slightly, as we transition into winter/summer.