gearroll

BICYCLE GEARING / ROLLOUT & CADENCE

What does one
crank turn cover?

Start with your wheel’s rolling circumference and tooth counts. Turn a gear ratio into metres per crank revolution and theoretical speed.

An engaged direct chain drive, no tyre slip. Enter your own measurements.

01 / YOUR INPUTS

One gear. One cadence.

Wheel rolling circumference

Enter circumference, not diameter or a tyre label. 2100 mm is an illustrative input, not a tyre-size lookup. Unit changes retain the physical value.

Engaged chain drive

Whole tooth counts. The front ring drives the rear wheel directly through the selected sprocket; internal hub or motor reductions are excluded.

Crank cadence

One complete pedal cycle counts as one crank revolution. Zero is accepted, but actual coasting speed is outside this driven model.

02 / THE DISTANCE PER TURN

Your rollout.

A RATIO IS A RELATIONSHIP

48 ÷ 16 = 3
wheel turns.

With the illustrative 2.1 m circumference, one crank revolution turns the wheel three times and covers 6.3 m. At an entered 90 rpm, that is 567 m per minute, or 34.02 km/h in the no-slip driven model.

The number describes the gearing. It does not say that you can sustain that speed, that the parts fit together, or that a particular cadence is suitable for you.

Read the derivation and worked comparisons →