Cycling Gearing Speed
Convert cadence and gear ratio into theoretical road speed.
Your numbers
Theoretical speed
Assumes no wheel slip and accurate loaded wheel circumference; wind and gradients affect the power required.
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Formula
Use v = c(F/R)C×0.06. c is cadence in revolutions per minute, F and R are front and rear tooth counts, and C is loaded wheel circumference in m. Speed v is in km/h.
Convert cadence and gear ratio into theoretical road speed.
Worked example
- Cadence (rpm)
- 90
- Front chainring teeth
- 50
- Rear sprocket teeth
- 25
- Wheel rollout circumference (m)
- 2.1
- Theoretical speed
- 22.68 km/h
- Distance per crank revolution
- 4.2 m
Scope and limitations
Assumes no wheel slip and accurate loaded wheel circumference; wind and gradients affect the power required.
Inputs are checked for missing values and allowed ranges. A result outside the finite numeric range is not displayed. Rounding affects display, while the calculation uses the model’s numeric precision.
Check your units and assumptions before relying on a result. Changing a label does not convert a currency or physical unit.
Formula version: 1f8ba44767c1 · Example checked: