Sprocket ratio to gear inches
Type a value in ratio to get it in gear in instantly.
That's 15× as tall as a sprinter’s top gear — nothing on our list beats it. At a steady 90 rpm that rolls about 793.3 km/h.
Convert the other way: gear in to ratio
What it means
How tall is that gear?
Wheel diameters include a typical tire for each size. A fat tire adds an inch or so, which is about 3% on the gear.
The math
How to convert ratio to gear in
Gear inches are wheel diameter × chainring ÷ sprocket. Development follows as gear inches × π × 0.0254 meters, and gain ratio as gear inches ÷ (2 × crank length). The figures below use the wheel selected above.
Example: 70 ratio = 1,841 gear in.
The table below is for 700c road, 25 mm tire (26.3 in).
Every unit
Your gear in every unit
Tables
ratio to gear in conversion table
| ratio | gear in |
|---|---|
| 20 ratio | 526 gear in |
| 30 ratio | 789 gear in |
| 40 ratio | 1,052 gear in |
| 50 ratio | 1,315 gear in |
| 60 ratio | 1,578 gear in |
| 70 ratio | 1,841 gear in |
| 80 ratio | 2,104 gear in |
| 90 ratio | 2,367 gear in |
| 100 ratio | 2,630 gear in |
| 110 ratio | 2,893 gear in |
| 130 ratio | 3,419 gear in |
gear in to ratio conversion table
| gear in | ratio |
|---|---|
| 20 gear in | 0.760456 ratio |
| 30 gear in | 1.14068 ratio |
| 40 gear in | 1.52091 ratio |
| 50 gear in | 1.90114 ratio |
| 60 gear in | 2.28137 ratio |
| 70 gear in | 2.6616 ratio |
| 80 gear in | 3.04183 ratio |
| 90 gear in | 3.42205 ratio |
| 100 gear in | 3.80228 ratio |
| 110 gear in | 4.18251 ratio |
| 130 gear in | 4.94297 ratio |
Quick answers
Quick answers
- How many gear in is 1 ratio?
- 1 ratio is 26.3 gear in.
- How many gear in is 10 ratio?
- 10 ratio is 263 gear in.
- How many gear in is 70 ratio?
- 70 ratio is 1,841 gear in.
The units
About these units
Sprocket ratio (ratio)
Chainring teeth divided by sprocket teeth, before the wheel is counted.
Gear inches (gear in)
The classic measure: the penny-farthing wheel your gear is equivalent to.
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