Adjusting ride power, (torque not zeroed)

velomanct

the one time i forgot to check to make sure torque was zeroed, it actually needed to be zeroed, for my race.
i was a little surprised to see i average 400watts for 20 minutes, looking at the downloaded ride data.

if my torque was 20 when coasting, is there any way i can adjust the power readings to be correct.
after looking at the download, my power seemed to hold steady at the 70-80watt range when coasting.(for some reason i never noticed this in the race.)
does that mean i should subract 70 or 80 watts from all the ride data?
260watts for 80minutes seems more realistic than 330watts.

ric_stern/RST

Never had this problem personally (i check the torque at the beginning of every ride), however, this was posted to the wattage list
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Look at a section where you know you were coasting, e.g. just after
you finished the time trial. Pick a representative value for the
torque zero.

Now correct torque for torque at zero power:

Torque(actual) = Torque(measured) - Torque(zero)

Then recompute power according to the following formula:

Power(Watts) = 1746*Torque(N-m)*Speed(km/hr)/WheelCircumference(mm)

WheelCircumference is the same thing as in setup,
about 2100 for 700C

In fact, any ride where the minimum torque is non-zero is
very likely to be in need of correction.
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and this
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http://users.icubed.com/~mayhew/mayhew.xls

paste in your data to the correct columns. set column B so that it
subtracts whatever your torque was off by, as determined above.
you can then paste the data from column C and G into the old .cvs file.
a big thanks to andrew coggan for creating this, as there's no way i could have
done the math.
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hope it works out
ric

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