Accuracy, Regulation, Break in? Myth or True?

[Nexus5]

Originally Posted by ttomczak

Recently, I bought a BNIB Rolex with a 3131 movement... It lost 7 seconds a day (and yes, I know there is over 82000 seconds in a day), but I wondered about it... I then bought a GMT (used), and it currently is running at -1 second per 24 hour period.

I have seen threads on getting it regulated, some with -1 second every two weeks (really?), and that if it's new, there is a break in period...

Since all of the modern Rolex's have the COSC certifications, I have to assume ALL of our movements have been broken in, even when we buy them new... My GMT, as have most of my Rolex's, has or is very accurate, but the 3131 which was slow per my others at -7 a day seemed to be a little strange... And I get that different people make our movements, etc...

Just wondering what everyone's opinion is on this... Is there really a break in period? Is Regulation worth it? And what do most accept as "accurate"? I know we are a demanding bunch!!!

Just curious...

Thanks!

My Rolex oyster 116000 was running +32spd on wrist and +8spd crown-up for the first 4 days out of the box (average +25spd). By the 8th day it was +7 crown-up and +53 on wrist (avg +22spd). On the 10th day it was +10.5 CU and -0.2spd on wrist (avg +2.2spd). My $60 vostok Amphibia took 3 weeks to break-in out of the box going from averaging +18.5, +22, +13, +14, +10 to +4.5. It's at +4.5 for 5 days now. Such erratic fluctuations shows that the break-in period is not a myth at least in my experience with a Russian movement 2416b and a 3130 with free spring parachrom hairspring. One took 3 weeks and the other 10 days. The Rolex may not have fully settled after 10 days but +2.2spd is still decent. Maybe another week will fully settle. The measurement is against an atomic clock at www.time.gov using an Android app "watchcheck" available from https://play.google.com/store/apps/d...ler.watchcheck



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