# Homework Help: Cycling Experiment

1. Jan 13, 2007

### australianschoolkid

Hello
I have to complete an experimental physics project for high school physics this year and with help of the physics forum member, chroot (https://www.physicsforums.com/showthread.php?t=149893), I have come up with the idea of looking in to a experiment like cycling physiological experiment with a heart rate monitor, like measuring power output at various heart rates.

I like this idea I wish to look into it more, but don’t have a power meter device (they work by measuring torque and wheel speed). I need a way of measuring torque, as I’ve been told torque x rpm = power. So we need to find a way to measure the torque of a bicycle wheel. I already have two types of trainers available (A trainer is a compact stand that attaches easily to the rear axle of your bicycle. The trainer holds your bike securely and provides pedalling resistance for your workout.)

The two types of trainers that I have access to are: a mag type trainer, which makes use of magnetic fields to generate resistance, and also have access to rollers, which consist of three revolving drums on which a bicycle can be ridden.

These trainers already include some kind of resistance device to load the cyclist. So by calibrating this resistance device I could find torque it requires to spin at a specific RPM.

The calibration would is the hard part, I need some way to apply a known torque and measure the resulting RPM. It has been suggested that use of an electric motor to drive the trainer's resistance could be an idea I can measure the motor's current consumption, and calculate its torque. If this idea was used, would I just attach the motor straight on to the wheel?, if so how?

So… my question is does anyone have any ideas of a way to find the torque of a bicycle wheel?
And does anyone else have suggestions / ideas on this experiment?

P.S. there is a rundown on the types of trainers on this website-
http://www.bikeline.com/feature/trainer/index.htm [Broken]

Last edited by a moderator: May 2, 2017