Power Reserve.... What Is It.... ?? (my views)

[acce1999]

And to add to this interesting issue:

The state of the mainspring tension has an amazing impact on accuracy. In the large number of postings we see here on the theme accuracy I am pretty certain very few take the state of the mainspring into consideration.

I have observed that with full (maximum) tension most Rolexes are dead on, but after 24 hours (even less) of sitting still they start to drift: Caliber 30XX and 313X starts to gain time, and during the last 4 to 8 hours they behave differently: 30XX slows dramatically and loses seconds per hour, whilst the 313X picks up a second or two more every hour.

My caliber 3186 (my guess) Ex II (M serial) is the most consistent one. Just losing fraction of seconds as tension drops. Perhaps helped by the new Parachrom balance spring.

Best,

A

[acce1999]

Originally Posted by acce1999

... and during the last 4 to 8 hours they behave differently ...

The last 4 to 8 hours of total available tension... most likely hours 40 to 48...