The Breitling Watch Source Forums

I'm pretty uneducated about the technical know-how of watch movements, but here's my scenario and question:

My 2007 Navitimer World was losing 10 seconds per day back in June, so I had it completely overhauled by Breitling Service. When I received the watch back, I found that it would gain 5 seconds per day when it ran normally, but would lose 5 seconds per day if I ran the chronograph all day long. I shrugged it off and decided that I would just run the chronograph every other day and figured that would even out the time discrepancy, which it has consistently done. But I still have lingering questions: is this normal, why is this happening, and can/should it be fixed (the work is still under warranty)?

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Breitling Navitimer 01 LE

Seems your watch is still running pretty much to spec. A little bit out maybe. My understanding is that the more parts that are engaged the more energy consumed running them, & the resultant loses attributable to same. The energy can't be destroyed so it's converted to other forms & lost in the process. Not sure if the variation should be that much over a 10 sec span. There are other factors but they should have been dialled out during regulating. It's a mechanical devise so minor variations will be observed. Would not worry me as it does not sound critical but if you are worried then take it back to the AD for a check.

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Jim

"You have Control".

Accuracy is always affected with the chronograph running. If you look at watch reviews in Watch Time if they are testing a chrono they will always report stats with and without the chrono running.

However, it's inaccurate to assume that will always result in the watch running more slowly. As with anything else in watches there as multiple variables but the two key ones are the increased friction in the running train caused by the engagement of the chronograph gears and the reduction in amplitude of the balance spring caused by a reduction in energy transfer through the escapement. Those two factors will have different impacts in different positions and can cause some wild swings - take a look at some of the Watch Time test results and you may see the same watch losing 10 seconds more in one position with the chrono on and gaining 10 seconds more in a different position.

Watches are typically regulated to as close to +/- 0 as possible (or maybe slightly fast) after service, but that is with the chrono off. It's definitely not an issue but you may want to time the watch with the chrono running and the watch left alone in different positions and you might find some variations in timekeeping.