Bicycle Gear Ratio Converter
Calculate gear ratios, gear inches, development, and speed for bicycle drivetrains
Gear Analysis
50:17
Ratio: 2.94
Gear Inches
86.85"
Development
6.93 m
Gain Ratio
6.49
Wheel Circumference
2,356.19 mm
Speed at 90 RPM
Speed (km/h)
37.42
Speed (mph)
23.25
Common Setups
Wheel Sizes
Understanding the Metrics
Gear Ratio: Chainring teeth divided by cog teeth. Higher = harder gear, more speed per pedal rev.
Gear Inches: Traditional measure equivalent to wheel diameter of a penny-farthing with same gear ratio.
Development: Distance traveled per pedal revolution. Most intuitive measure for comparing gears.
Gain Ratio: Sheldon Brown's preferred measure. Accounts for crank length; tells you the mechanical advantage.