Bicycle Gear Ratios and Meters of Development

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A ride in the park or around the block is a regular activity for many of us. We cruise down hills and change gears for easier pedaling up the hill. But have we ever stopped to wonder how our bicycle gears work? What is actually happening when we shift gears up and down? This Demonstration represents an analysis of how the gears of a bicycle transfer energy from each crank rotation to the rear wheel. Specifically, it will show which sprocket combinations produce the greatest wheel distance for each complete pedal turn.

Contributed by: Tom Falcone and Ivan Moore (March 2011)
Open content licensed under CC BY-NC-SA



The front sprocket control is set for the common number of teeth on a typical bicycle chain sprocket.

The rear sprocket control is variable from 9 to 34 teeth, which are common rear gear tooth counts.

The rear wheel diameter, measured in inches, can be changed to select typical bicycle wheel diameters.

Meters of development measures the distance in meters traveled by the rear wheel for one revolution of the front sprocket. This term is called "gear inches" in the U.S.

The rotation angle can be animated to rotate continuously. Slower speeds work best.

Special thanks to Dr. Steven Broad for assistance and direction in creating this project.

Many thanks to Dr. Alex Hahn and the National Science Foundation for sponsoring the RET program at the University of Notre Dame.

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