Calculate gear inches, development, and speed for any chainring, cassette, and tyre combination.
Lowest gear
2.86m
Highest gear
9.57m
Gear range
3.35x (235%)
Effective gears
~16 of 22
| Cog | 50t | 34t |
|---|---|---|
| 11t | 4.55 9.57m 51.7 km/h | 3.09 6.51m 35.1 km/h* |
| 12t | 4.17 8.77m 47.4 km/h | 2.83 5.96m 32.2 km/h* |
| 13t | 3.85 8.10m 43.7 km/h | 2.62 5.51m 29.7 km/h* |
| 14t | 3.57 7.52m 40.6 km/h | 2.43 5.11m 27.6 km/h* |
| 15t | 3.33 7.02m 37.9 km/h | 2.27 4.77m 25.8 km/h |
| 16t | 3.13 6.58m 35.5 km/h* | 2.13 4.47m 24.2 km/h* |
| 17t | 2.94 6.19m 33.4 km/h* | 2.00 4.21m 22.7 km/h* |
| 19t | 2.63 5.54m 29.9 km/h* | 1.79 3.77m 20.3 km/h |
| 21t | 2.38 5.01m 27.1 km/h* | 1.62 3.41m 18.4 km/h |
| 23t | 2.17 4.58m 24.7 km/h* | 1.48 3.11m 16.8 km/h |
| 25t | 2.00 4.21m 22.7 km/h* | 1.36 2.86m 15.5 km/h |
* Highlighted cells indicate gears that overlap between chainrings (less than 4% development gap). Speed shown at 90 rpm.
Gear ratio = chainring teeth / cassette cog teeth. A larger ratio means a harder gear.
Gear inches = ratio x (tyre circumference / 25.4 / pi). This is the traditional way to compare gears across different wheel sizes.
Development = ratio x circumference / 1000, measured in metres per pedal revolution. This tells you how far you travel with one complete turn of the cranks.
Speed = development x cadence x 60 / 1000. This is your road speed at a given cadence.
Sources: Sheldon Brown, Sheldon Brown tyre table, Westchester Cycle Club
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