- #1

DannoXYZ

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**Pedal-force for bicycle @ 43.2mph ?**

I heard that bike-racers can put put 1500 watts in sprints. Using this site: http://www.noping.net/english and entering the following:

- Racing bike - hands on the drops

- weight = 170 lbs

- power = 1500 watts

Then hit CALCULATE button and I get a speed of

**43.2mph**. I came up with this diagram to figure out all the forces and torques in order to come up with pedal-force:

**0.336m = Wr = Wheel Radius**

0.170m = CL = Crank length

0.170m = CL = Crank length

Given 52x13t gear ratio of 4:1, Tc = 4*Tw; torque at crank is 4x higher than torque at wheels.

Then using this site: http://www.analyticcycling.com/GearCadenceSpeed_Page.html, I enter:

speed = 43.2mph

chainring = 53t

cog = 13t

wheel-diameter = 0.672m

Click on RUN MODEL and I get

**135 rpms at the crank**.

What stops me next is how to figure out what PF - pedal force is in order to generate 1500w and go 43.2mph @ 135rpms. ?

Thanks.

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