The Breitling Watch Source Forums

Well that makes more sense than a one off loss.

If you lay your watch on it's side at night try laying it on its back - that will tend to speed it up.

The change could be because of the way you wear it, the temperature, etc and it will behave differently for you than the previous owner because you wear it differently. It could also have had a minor knock - but 6 to 9 seconds a day is outside of COSC specs (-4 to +6 seconds per day) so you can have it regulated under warranty. Depending on whether your local AD is a service centre they may be able to regulate it on site - takes about 10 minutes.

I did use one of those hand-crank flashlights with the watch on (I cranked it), and that seems to be around the time it started running slow. Could that have anything to do with it or is it probably just a coincidence?

Sounds like coincidence.

Now my watch is losing about 3 to 6 seconds per day. I don't understand how it went from keeping perfect time to running slow. Should I send it in to Breitling to have it fixed under warranty?

As I have already said, it's settling down - adjusting to a new routine. COSC specs are up to -4 seconds a day slow. Don't worry about it, wear it for a few weeks and see what happens. Use the advice to lay it in different positions to help control the difference if it makes you feel better, but the best thing you can do is not worry about whether today's error is 3 seconds or 5 seconds for a few weeks and then check it again.

Ok, thanks. Sorry, I was confused...I didn't understand that it has to adjust from the previous owners routine to my routine, and I was confused as to how it could keep perfect time for about 5 days and then start running slow. I will wait and see what happens. Thanks again for your help.

Well, a great many 'theories' have been contradicted by empirical observations.

I know what I've seen.

I don't intend to debate it.

I posted the explanation the following morning when I had more time. If you wish to consider that explanation as the equivalent to an explanation as to why the Earth is flat then that is your right. I won't be offended

As Roff has explained the physics of this, I won't add to it except to say he is exactly correct and can be easily demonstrated by looking at any pendulum clock. By adjusting the weight at the bottom of the pendulum you can shorten or lengthen the pendulum thereby increasing or decreasing the beat. The principal works exactly the same with a balance wheel on a clock or watch. All factors being equal, the watch or clock will run faster when the spriing is near the end of power. However, all factors are never equal , and one might observe different behavior caused by other factors. Since watches are adjusted for variences in spring power (isochronism) you really don't expect much change in rate, but it is there.
Undoubtedly the sudden and consistent change described has been caused by other factors. This is why quartz watches are so popular with the general public. IMO, If you buy a watch just for the timekeeping, don't buy a mechanical one. Sooner or later it will not keep good time.

Are you actually trying to compare a theory made through ignorance, to a theory based on the laws of physics?

I mean really, are you sure you want to go down that route? Really?

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Could magnetism / demagnetism caused this behavior? I.e., maybe you've placed the watch on top of/near a massive subwoofer, or microwave oven or something? Though for my own watches, I've never actually placed close attention to what my tiny "second" hand is doing...

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a few Pams...

Magnetism will almost always speed the watch up, and the affect will be a lot more dramatic than a few seconds - minutes a day at least, and often hours.

Magnetism usually affects the hairspring which is curled into a spiral. When it becomes magnetised the loops tend to 'stick' together effectively shortening the hairspring and increasing the rate of the watch.

So I have taken notice of the time keeping over the past week, and the watch loses about 4 seconds per day (over an 8 day period). Since I am still under warranty for another 13 months, I don't think I am going to worry about it unless it gets really bad. Thanks for all the help, guys.

-4 seconds is within COSC specs, so nothing wrong. Additionally, the accuracy is clearly improving as the average loss is less than you reported last week.

I've been following this thread for a while just to see where it goes. I notice that some people observe that their watch gains time as the power diminishes, while others witness a loss.

As has been discussed above, typically a watch will run faster because of the reduced balance wheel amplitude. Notice I say typically. Another factor in the rate of the watch is the regulator. It is a device that is adjustable over a small range that effectively changes the length of the hairspring thus controlling the rate.

In early watches the regulator is two brass pins that sit on either side of the spring. When the balance is in motion, the spring contacts each pin alternately as it expands and contracts. The watchmaker can bend the pins slightly to adjust the width of the gap. This adjustment is primarily used to control isochronism, the phenomena we are discussing here.

In later Swiss watches the regulator consists of a brass block on one side with a pin on the other side that can be rotated to open the gap for removing the balance wheel from the bridge. The gap in this regulator is fixed and very little adjustment can be made to the width. It is critical that the hairspring be centered in this gap when the balance is a rest. If it is not, there is a very real possibility that the hairspring will not contact both sides of the regulator when the power is reduced. This will effectively lengthen the hairspring making the watch run slower.

I write this to explain that nothing is absolute when it comes to a mechanical device such as a watch. The laws of physics still apply. It is just that we are dealing with many, not just one.

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