Gear Inch Calculator
Gear Inch Calculator ! By Warren Beauchamp     
  • To use this gear inch calculator, you'll need to measure the height of your (loaded) rear tire, and know how many teeth are on the chain rings in question.
  • Or... see for tire sizes
  • Leave the Rohloff/Schlumph ratio settings at "1" if you don't have one.
  • Use ".4" for the Schlumph type1 "2.5:1" ratio and "1.65" for the type2 "1:1.65" ratio.
  • Use 1.462 for the Rohlhoff 14 speed hub
  • Leave the Intermediary gear settings at "1" if you don't have an intermediary gear or jackshaft.
  • At 110 gear inches, you'll spin out at about 40MPH.


Drive wheel diameter: Inches
Rider Cadence: RPM
Crank chain ring: Teeth
Rohloff/Schlumph ratio:
Intermediary gear (crank side): Teeth 
Intermediary gear (hub side): Teeth
Drive hub gear: Teeth
Drive train gear Inches =  95
Speed at specified cadence =   28.362 MPH

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