Gear calculator
Check your rollout and speed before your next road, track or time trial ride.
Your setup
Typical rolling circumference; actual tyres vary by rim and pressure.
At your chosen cadence
Speed42.9 km/h
Rollout / pedal turn7.16 m
Gear ratio3.40 : 1
One full turn of the pedals moves the bike approximately 7.16 metres.
Enter valid positive values in the indicated ranges.
Compare nearby sprockets
| Gear | Rollout | At 100 rpm |
|---|
Estimates assume no tyre slip. Check current race regulations separately before using a gear in competition.
How rollout works
Wheel circumference × chainring teeth ÷ sprocket teeth gives the distance travelled with one full turn of the pedals. Real tyre circumference varies, so measure it when precision matters.
Find a gear
Match a target rollout
Enter the distance you want per pedal turn, then choose your wheel and tyre size.
Circumference estimate uses wheel bead diameter and nominal tyre width. Measure your actual tyre circumference for precise rollout.
| Chainring × sprocket | Rollout | Difference |
|---|
Enter a target rollout between 2 and 15 metres.