I think the key to getting consistent spin down numbers is to be consistent in how you do them. Since the PP is looking at the rate of deceleration after you stop pedaling at the target speed, I try to make it so that I'm VERY slowly approaching that target speed and then stop. In other words, I think it might get "confused" if the speed is actually increasing quickly just before you stop pedaling. In any case, my spin downs don't vary by more than a unit or two.

Spin down calibration should just be a "once in a while" sort of thing. Do it after the unit is well warmed up, and then don't bother doing it again for a long time. After all, about the only thing that will change it is wear, or "breaking in" of the unit. So, occasionally doing the spin down to compensate for that will be a good thing. I can't imagine that doing it more often than every couple of hundred hours of use would really gain anything.

As far as losing the data goes...I haven't experienced that yet. Then again, my time on it is somewhat limited (my son actually has used it more than I have). My only complaint about the data download is how LONG it takes to write to the USB stick :-/

BTW, the percent difference I see between the Quarq and the PP is about what I'd expect there to be for drivetrain losses, which means that the PP should give a rider power numbers close to what they would expect for a PT. When you think about it, that's good, because I would expect the PT users who purchase a Revolution to be more likely to buy the Power Pilot than other PM users ;-)

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