It doesn't, power is calculated from hub torque and hub speed.BillM said:1. How does PTap even know crank torque...and
PowerTaps read about 1-2% less power than the crank sensing SRM. Drivetrain efficiency is lower at higher cadences. There's little significance in the difference, IMO.BillM said:2. What is the significance in the difference?
Will this point to an inefficiency in the drivetrain? What is a normal variance between the two numbers?
BillM said:1. How does PTap even know crank torque...and
2. What is the significance in the difference?
Will this point to an inefficiency in the drivetrain? What is a normal variance between the two numbers?
Gotcha. I suspected as much...thanks for confirming.jws said:1) CPS calculates crank torque via PT hub torque, speed and cadence.
2) crank torque is hub torque times the gear ratio.
drivetrain inefficiency will be ignored in the calc. by CPS since crank torque is merely back-calculated.
Cool, that must be new in WKO+. I'm not sure what that'd be used for, but maybe it'll be interesting when I start my iso-power intervals on the trainer this fall. Or wait... this is exactly what my SFR workouts have been lacking!jws said:1) CPS calculates crank torque via PT hub torque, speed and cadence.
Useful for Quadrant Analysisfrenchyge said:Cool, that must be new in WKO+. I'm not sure what that'd be used for, but maybe it'll be interesting when I start my iso-power intervals on the trainer this fall. Or wait... this is exactly what my SFR workouts have been lacking!
I am trying to Custom Periodic Chart to show Crank Torque for specific CPs 5 secons 3 minutes etc. But they all come out as Zero I know it is a calkculated number, but why have the option in Channel if all you get is zero?frenchyge said:Cool, that must be new in WKO+. I'm not sure what that'd be used for, but maybe it'll be interesting when I start my iso-power intervals on the trainer this fall. Or wait... this is exactly what my SFR workouts have been lacking!
Certainly crank torque is more useful to have on the graph than hub torque, since it allows you to see the gear changes.
Not to mention better data to confirm your 40% increase in power due to (secretly) using PowerCranks all winter.frenchyge said:this is exactly what my SFR workouts have been lacking!
I'm detecting, and it is every so slight, a sense of sarcasm towards PowerCranksRapDaddyo said:Not to mention better data to confirm your 40% increase in power due to (secretly) using PowerCranks all winter.
Who, me? Not a chance. The 40% improvement figure (I think I have that right) has been stated in promotional material about the PowerCranks. And, of course, I take promotional claims at face value, don't you?Lucy_Aspenwind said:I'm detecting, and it is every so slight, a sense of sarcasm towards PowerCranks
RapDaddyo said:Not to mention better data to confirm your 40% increase in power due to (secretly) using PowerCranks all winter.
Absolutely. Unquestionably so, to be more precise.RapDaddyo said:Who, me? Not a chance. The 40% improvement figure (I think I have that right) has been stated in promotional material about the PowerCranks. And, of course, I take promotional claims at face value, don't you?
jetnjeff said:I am trying to Custom Periodic Chart to show Crank Torque for specific CPs 5 secons 3 minutes etc. But they all come out as Zero I know it is a calkculated number, but why have the option in Channel if all you get is zero?
Yeah I have Cadence recorded. Funny that Crank Torque would be available as a channel and not work. Bust be a bug.jws said:your cadence might not be working; if cadence is missing, cps can't calculate crank torque.
after trying it myself, it doesn't work for me either, so maybe cps won't do it!
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