Skip to content
ENExplore Calculators

Bike Gear Ratio Development Calculator

Work out bike gear ratio development instantly with clear inputs, formula shown and shareable results.

About Bike Gear Ratio Development Calculator

Development is the distance travelled per pedal revolution: gear ratio times wheel circumference. A 50/14 with a 0.67 m wheel gives a 3.57 ratio and 7.52 m per turn, so 90 rpm produces 40.6 km/h. Gear inches, the older measure, expresses the same thing as the diameter of an equivalent direct-drive wheel.

Formulas

Gear ratio

ratio = chainring teeth / sprocket teeth

Development

development = ratio x pi x wheel diameter

Worked example

With the default values below, Bike Gear Ratio Development Calculator returns Development Per Pedal Revolution of 7.517. Change any input above and every figure here is recalculated in your browser.

Inputs used

Chainring teethminimum 1
50
Rear sprocket teethminimum 1
14
Wheel diameter including tyreminimum 0.1 m
0.67 m
Pedalling cadenceminimum 1 rpm
90 rpm

Results

Development Per Pedal Revolution
7.517 m
Gear Ratio
3.571
Speed At That Cadence
40.59 km/h
Gear Inches
94.2

Step by step

  1. 1Values used
  2. 2Gear ratio
  3. 3Development
  4. 4Development Per Pedal Revolution= 7.517 m
  5. 5Gear Ratio= 3.571
  6. 6Speed At That Cadence= 40.59 km/h
  7. 7Gear Inches= 94.2

Assumptions and limits

  • The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
  • In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
  • Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
  • This is an estimate from population-average equations, not a medical or diagnostic assessment. Individual results vary with genetics, training history and technique. Seek advice from a qualified coach or clinician before making significant changes to training.
  • This is an estimate for general information and not professional medical advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

This is an estimate from population-average equations, not a medical or diagnostic assessment. Individual results vary with genetics, training history and technique. Seek advice from a qualified coach or clinician before making significant changes to training.

Frequently Asked Questions

Why do riders talk about gear inches?

It survives from penny-farthing days, when the gear literally was the front wheel diameter. It remains handy for comparing setups across wheel sizes.

What development suits climbing?

Around 2.5-4 m per revolution, so that a steep gradient can be ridden at 70-90 rpm rather than grinding at 50.

Related Calculators

Bike Gear Ratio Development Calculator | Calcrivo