Strange timing behavior on Royal Oak 15500

[ericmeds]

Can't seem to make sense of this -

When 15500 is fully wound, it is super accurate and loses almost no time.

When it is 40% or less wound, it runs 5-10 seconds FAST per day.

I would think it would be the other way around!


It often is running fast because it does not reach its full potential of 60-70 hours on the wrist (due to some kind of winding inefficiencies) unless wound up manually.

[drhk]

That it is most accurate when fully wound is how it should be. Automatic watches are supposed to be (almost) fully wound when worn, hence, adjusted to max accuracy in this state.

The accuracy changes with the tension of the spring. However, the way it changes (faster or slower) depends on the design of the watch movement (its isochronism error), which - on top - even may not be identical for one and the same movement. i.e. a watch may run slightly faster when less wound while a second watch of the same reference might even run slightly slower.

However, I think that 5-10 seconds fast at 40% might not be within the normal range. Maybe have it checked by AP service.

[MrBlahBlah]

I’d have it checked, for sure, that’s not quite up to their standards


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