Got some new flat pedals, not quite free spinning. So I was thinking about it.

The math is simple. I guess a stiff pedal probably won't spin if you set a nickle on it near the reflector. I guess 20 nickles would do it easily though, in a really bad case, so 100g? at what 5cm, let's just say 6? so that's .1kg*.06m*9.8m/s^2 or about .06N*m torque?

Torque can be thought of as units of Joules (N*m) per radian so mulitplying by 2 pi gives joules per turn or about 0.4 J/turn. At a cadence of 90 you have 1.5 turns per second so that's about 0.6 J/s or 0.6 watts. Times two legs gives about 1.2 watts.

Certainly that's not a big deal, but if it were 10 times lower then I'd probably say it's completely irrelevant (maybe not for a pro still).

Anyway let's just say that implies .06 watts per nickel of resistance. That's in SI W/Nk units.

Time to go tape some coins to some pedals.