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THE FEUTEX TOOLKIT

Bicycle Gear Development

Calculate travel per crank turn and speed for a selected chainring, sprocket and cadence.

Cycling workspace● Runs in your browser
01 Your input
02 Your result
View or copy raw result data
FormulaDevelopment = circumference*chainring/sprocket; Speed = circumference*chainring/sprocket*cadence*60/1000

Worked example

Inputs

Chainring
50 teeth
Sprocket
25 teeth
Circumference
2.1 m
Cadence
90 rpm

Expected results

Development
4.2 m/revolution
Speed
22.68 km/h

Load the example in the workspace to reproduce these results. Display rounding does not change the underlying calculation.

How to use this tool

  1. Enter the measured quantities and your own planning assumptions.
  2. Review all calculated outputs and the stated limitations.

Try this example

{
  "chainring": 50,
  "sprocket": 25,
  "circumference": 2.1,
  "cadence": 90
}

Accuracy and scope

Assumes no wheel slip. Use measured loaded rolling circumference for better accuracy.

Is my data uploaded?

This tool runs locally in your browser. Input and output are not sent to a processing server. Copy or download your result before leaving the page.