8 Services from bike-calc.x402tookit.com

Returns a full gear-inch and speed table for every chainring/cog combination in a drivetrain, including range, step percentages, and duplicate gears.

Calculates the required bicycle chain length in links (rounded up to the nearest even number) from chainstay length, chainring teeth, and rear cog teeth.

Calculates the cadence needed to hold a target speed in a given gear, or the chainring-to-cog ratio needed to reach a target speed at a given cadence.

Calculates gear ratio, gear inches, development per pedal turn, and speed at a given cadence for a specific chainring and cog combination on a bicycle wheel.

Calculates recommended starting saddle height from inseam using the LeMond (×0.883) and Hamley (×1.09) formulas, plus the Holmes knee-angle range check.

Estimates bicycle frame size (seat tube in cm and S/M/L letter size) from inseam measurement and bike type, with an optional height-based letter size cross-check.

Returns rolling circumference, diameter, and revolutions per km for a given tyre size, either from a preset tyre label or from rim bead seat diameter and tyre width.

Calculates gradient percent and angle from rise and distance, plus climbing rate (VAM) and time to climb at a given rate.