How is an ultra-long power reserve achieved?

[reddog4063]

Some competitor watch brands are able to achieve ultra-long power reserves (up to 192 hours or more) whereas Rolex seems to either have 40 hours (barely) or 70 hours in most of their models. How is this achieved and why doesn't Rolex pursue longer reserves? Does having a longer power reserve make for a watch that requires a shorter service interval (perhaps due to a weak point like a longer mainspring, etc)?

[Tools]

Magic..


Some use multiple mainsprings, so they give up torque (long, thin, multiple mainsprings, vs. a thicker, stronger spring) for a longer power curve. Whether this has any actual practical, or longevity, benefits is still unproven.

[Onikage]

As I understand it longer power reserves suffer from greater accuracy deviations when running low or high on power. I'm sure there's more to it but a longer reserve basically means a longer mainspring at higher and lower tension respectively.

[reddog4063]

If its true that the longer mainspring would lose tension more quicker when wound down or be too tense when overwound, then i suppose these longer and longer power reserves are mostly a marketing gimmick and i would understand why rolex wouldnt pursue it.

Anyone have one of these models and put them to the test on a timegrapher?

[Ian Macdermott]

Originally Posted by reddog4063

Some competitor watch brands are able to achieve ultra-long power reserves (up to 192 hours or more) whereas Rolex seems to either have 40 hours (barely) or 70 hours in most of their models. How is this achieved and why doesn't Rolex pursue longer reserves? Does having a longer power reserve make for a watch that requires a shorter service interval (perhaps due to a weak point like a longer mainspring, etc)?

Rolex knows no one wears their watch for more than a day or two so why bother.