The Breitling Watch Source Forums

Just a curious question from a newbie to the higher end watches. When one says a watch is +/- x seconds a day, how do they arrive at this. I am OCD about some things and have been looking all day to try ad find out how to determine this. Maybe I have overlooked it on the forum posts, so if that is the case can someone please point me to the link.

TIA

John

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Chronomat GT
Colt Automatic
SS Rolex Datejust

It means that the normal operations of your watch is +/- seconds per day.

For example, a mechanical COSC certified watch is going to be from -4 seconds a day to +6 seconds a day. That means that if you're watch is COSC certified, you're watch is not suppose to lose more than 4 seconds in a day or win more than 6 seconds in a day.

That is the normal operation range for a mechanical COSC certified watch. If you receive you're new watch and it's losing more than that or gaining more than that in a day, there is a problem with it and the warranty covers that.

Hope that helps a bit.

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Mat

Breitling Navitimer 01
Omega Seamaster 300mc
Omega Speedmaster Pro "Mitsukoshi Mod"
Seiko Prospek Orange Samurai

Sync your watch with an atomic clock, or a site like time.gov, and make note of the time. Check back after a few days or a week and see how far the time has deviated from the original sync. Divide it and figure out the average daily variation.

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-RJ

For Chronometer watches the COSC institute tests the timekeeping of a movement over a period of time at different positions and at a couple of different temperatures. The idea is to simulate "real world" conditions while keeping the procedure as standardised as possible. All being well, this should then translate quite accurately into the actual timekeeping of the finished watch when it's on your wrist.

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Driver8

Site Moderator

im noticing that my 2 month old navi world is +. Last night at 6pm I noticed it was 2 minutes ahead, i set it to US Naval time, and this morning it is 2 seconds fast. i will monitor tonight and see if its within the allowable range.

does any one else experience this? any suggestions?

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Navitimer World Black Face, SS Bracelet.

Rarely is a mechanical watch ever exact. COSC specs say that -4 to +6 seconds per 24 hours is acceptable. If your watch is outside those specs, Breitling will adjust it for you. If yours is +2 overnight (presumably 12hrs?), then you are at about +4 daily, which is perfectly acceptable.

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-RJ