Gear calculator
50/34 compact, 11-28, 28 mm · sets how strictly gaps are judged
20–120 teeth
9–60 teeth
Measured rollout
If you have rolled your wheel out and measured it, enter that here. It replaces the wheel and tyre sizes and removes the nominal-width error entirely.
mm per wheel revolution
Wheel 678 mm · rolls 2130 mm per turn
15 of 22 combinations, in the order you would actually ride them. The rest are cross-chained or out of reach.
| Gear | Step | grind60 rpm | normal90 rpm | spinny110 rpm |
|---|---|---|---|---|
| 34 × 281·111.21 | — | 9.3 | 14.0 | 17.1 |
| 34 × 241·101.42 | 16.7% | 10.9 | 16.3 | 19.9 |
| 34 × 211·91.62 | 14.3% | 12.4 | 18.6 | 22.8 |
| 34 × 191·81.79 | 10.5% | 13.7 | 20.6 | 25.2 |
| 34 × 171·72.00 | 11.8% | 15.3 | 23.0 | 28.1 |
| 34 × 161·62.13 | 6.3% | 16.3 | 24.4 | 29.9 |
| 50 × 212·9+32.38 | 12.0% | 18.3 | 27.4 | 33.5 |
| 50 × 192·82.63 | 10.5% | 20.2 | 30.3 | 37.0 |
| 50 × 172·72.94 | 11.8% | 22.6 | 33.8 | 41.3 |
| 50 × 162·63.13 | 6.3% | 24.0 | 35.9 | 43.9 |
| 50 × 152·53.33 | 6.7% | 25.6 | 38.3 | 46.9 |
| 50 × 142·43.57 | 7.1% | 27.4 | 41.1 | 50.2 |
| 50 × 132·33.85 | 7.7% | 29.5 | 44.2 | 54.1 |
| 50 × 122·24.17 | 8.3% | 31.9 | 47.9 | 58.6 |
| 50 × 112·14.55 | 9.1% | 34.9 | 52.3 | 63.9 |
Wheel and tyre tables v2026-08-12 · sizes pending source verification
Notes
The three cadences
Grind, 60 rpm — pushing a big gear slowly. Normal, 90 rpm — where most riders settle; if you read one column, read this one. Spinny, 110 rpm — light-legged, sprinting or spun out.
What the step colour means
Green is a smooth gap, amber noticeable, red hard. The same percentage is not the same problem everywhere: air resistance rises with the cube of speed, so holding your cadence through a 10% jump costs about 10% more power on a climb and about 30% at 40 km/h. And a gap a road rider notices, a mountain biker never will — so the thresholds follow the Riding setting.
A grey row is a gear that duplicates the one above it.
The three views
As you ride drops the combinations you would never use and shows what is left in the order you would actually ride it — up one ring, change ring once, carry on. By chainring shows how the bike is built instead, and By speed puts every gear in order, which exposes duplicates and gaps.
On a 50/34, As you ride leaves 15 of 22 combinations, and the ring change works out at 12% — smaller than the biggest jump on the cassette itself. That takes dropping three sprockets as you shift the front, which is what riders and electronic groupsets both do; +3 beside a gear is how many extra sprockets it costs. On a wide pairing like GRX 48/31 the same trick turns a 37% hole into 11%.
What the numbers assume
The speeds are exact arithmetic — your gear ratio times how far the wheel rolls, nothing else: no rider, no wind, no hills. The step colours are the opposite, our judgement of how a gap feels, weighing air resistance against the kind of riding you picked.
Stock cassettes
Press Find beside the sprockets field to search all 221 by range, brand or model — the big sprocket matches on first digits, so 10 4 finds every 40-something bottom gear. Or browse the full list, where every cassette links straight back here set up on a bike that suits it.