Huge difference in standing versus seated power

[flapsupcleanup]

I'm not sure I agree with you on this one frenchy. If it calculates power based on hub rpm, then for a given power and speed your torque would have to remain constant regardless of the gear (cadence) you picked. But if you double your cadence, you halve the torque (at the pedals) to maintain the same power.

Wait! I'll reply to my own post. Even though the pedal torque is cut in half above, because of picking a lower gear and therefore a larger moment arm at the rear cogs, the hub torque remains the same. And it works out. I stand corrected....by myself! I just love talking to me.

 

[frenchyge]

But if you double your cadence, you halve the torque (at the pedals) to maintain the same power.

That's true, but how'd you double your cadence and keep speed the same? By changing to a lower gear, of course, which changes the ratio of crank-arm torque that is transferred to the hub. Drive speed (rpm) from the pedals to the hub is multiplied by the transmission gear ratio, but torque is divided by the gear ratio, so that power remains constant regardless of gear selection.

In other words, changing gears may change pedal torque, but it doesn't change hub torque. Hub torque is a function of motion resistance only, whereas pedal torque varies with gear selection, too.

 

[frenchyge]

Wait! I'll reply to my own post. Even though the pedal torque is cut in half above, because of picking a lower gear and therefore a larger moment arm at the rear cogs, the hub torque remains the same. And it works out. I stand corrected....by myself! I just love talking to me.

Sorry, I was already typing a response. Your correction stands correctly, however.