⚙️ Gear Ratio Calculator
See your speed for every gear combination at any cadence.
Drivetrain Presets
Cassette
Wheel size
Tire width (mm)
Speed at 90 RPM (mph) — cross-chain combos marked ⚠
| Ring ↓ / Cog → | 11T | 12T | 13T | 14T | 15T | 17T | 19T | 21T | 24T | 28T |
|---|
| 50T(4.5–1.8) | 32.2 | 29.5 | 27.2 | 25.3 | 23.6 | 20.8 | 18.6 | 16.9 | 14.8⚠ | 12.6⚠ |
| 34T(3.1–1.2) | 21.9⚠ | 20.1⚠ | 18.5 | 17.2 | 16.1 | 14.2 | 12.7 | 11.5 | 10.0 | 8.6 |
Lowest gear8.6 mph
Top gear32.2 mph
Range3.7×
Wheel circ.211.1 cm
⚠ Cross-chaining (big ring + biggest cogs, or small ring + smallest cogs) causes extra chain wear — avoid for extended efforts.