Sheldon Brown's | 
| Internal Gear Calculator |
|---|
by Sheldon "Gain Ratio" Brown
Click here for the version for conventional gearing.
Click here for older, rare internal hubs.
The SRAM/Sachs 3 x 7, 3 x 8 and 3 x 9 and the Sturmey-Archer CS- RF3 and CS-RK3
are the only production internal-gear hubs designed to use more than one rear sprocket,
but other models are included in the list for the benefit of tinkerers.
Gain Ratios |
Gear Inches |
Meters Development |
About Percentages |
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If you want more numbers, including speed and cadence data,
Jake Odell has a more elaborate gear calculator:
HPV Drivetrain Analyzer
Tom Kunicki has a calculator with specific features useful for fixed-gear and singlespeed riders:
"Rabbit, a Singlespeed and Fixed-gear Calculator"
John Allen has pages giving exact, fractional ratios calculated from gear tooth counts:
Drive ratios of bicycle hub gears