39×36 ratio 1.083 — 2.28 m per stroke
A 39-tooth chainring with a 36-tooth sprocket gives a ratio of 1.083. One pedal stroke carries you 2.28 m, and at 90 rpm that is 12.3 km/h.
Speed
Speed is the ratio multiplied by cadence. Grinding a big gear slowly and spinning a small one quickly give the same speed, but legs last far longer doing the second — which is why most riders pick the gear that keeps them near 80 to 90 revolutions a minute.
- Cadence 60 rpm8.2 km/h
- Cadence 80 rpm10.9 km/h
- Cadence 90 rpm12.3 km/h
- Cadence 100 rpm13.7 km/h
- Chainring
- 39T
- Sprocket
- 36T
- Gear ratio
- 1.083
- Per pedal stroke
- 2.28 m
- Gear inches
- 28.5
Nearby cells
Same chainring, other sprockets
Same sprocket, other chainrings
Worth knowing
- The ratio is the chainring divided by the sprocket — bigger means harder and further.
- Two combinations with the same ratio are the same gear, whatever the tooth counts.
- Speed is ratio times cadence, so neither number settles it alone.
- These figures assume 700×25C wheels with a 2,105 mm circumference.
Common questions
Q. What is the ratio of 39×36?
1.083. One pedal stroke carries you 2.28 m, which is 28.5 gear inches.
Q. How fast is this gear?
At 90 rpm it works out to 12.3 km/h. Speed scales with cadence, so 60 rpm gives two thirds of that and 100 rpm a little more.
Q. Is there another combination that feels the same?
No other combination in this table sits within 1 % of this ratio.
Q. What happens one sprocket lighter?
There is no lighter sprocket in this table. For steeper climbs you would drop to a smaller chainring.