The Breitling Watch Source Forums

Wow a new "flyback complication"!!!! Sorry just joking...:p

It was running in their case for a while so prob fine.

I find this strange though... Are you saying they're supposed to leave the factory intentionally outside of COSC to then later settle? I've seen debates on this and it just doesn't make sense. The watch comes with a COSC certification, not a guarantee that it will fall back to COSC in 6 months. It should be there from day 1.

If only physics were that simple.

Let's start at the beginning. The watch is not COSC certified. The movement is certified by the COSC before it is cased up. Once the COSC is issued it is good for life and proves that the movement can perform within COSC specs. Once it comes back from COSC it is cased up, potentially having been partially or completely disassembled and then reassembled and is regulated. A watch that performs within COSC specs can be regulated to be minutes a day fast or slow if the watchmaker so chooses, but in reality it will likely be regulated to run a little fast, often outside of COSC specs. That is because once the watch is worn all day every day it will settle - oils will move around, the hairspring properties will change from weeks on end of being stretched and then returning to shape, the mainspring will go through multiple cycles of being wound and unwound, etc, etc.

All of these will have a tendency to have the watch slow down by a few seconds a day over the first 6 weeks of use where it will then remain (all other conditions being equal) until it is in need for a service.

If only physics were that simple. Let's start at the beginning. The watch is not COSC certified. The movement is certified by the COSC before it is cased up. Once the COSC is issued it is good for life and proves that the movement can perform within COSC specs. Once it comes back from COSC it is cased up, potentially having been partially or completely disassembled and then reassembled and is regulated. A watch that performs within COSC specs can be regulated to be minutes a day fast or slow if the watchmaker so chooses, but in reality it will likely be regulated to run a little fast, often outside of COSC specs. That is because once the watch is worn all day every day it will settle - oils will move around, the hairspring properties will change from weeks on end of being stretched and then returning to shape, the mainspring will go through multiple cycles of being wound and unwound, etc, etc. All of these will have a tendency to have the watch slow down by a few seconds a day over the first 6 weeks of use where it will then remain (all other conditions being equal) until it is in need for a service.

I thought I'd report back now that's it been a couple months with the latest watch. It has in fact slowed down a little and is now running at about +0.4 sec/day. I'm very impressed. All is well that ends well!