Mountain-Biking Calculators
Free, practical calculators for setting up and maintaining a mountain bike — tire pressure, gear ratio, suspension sag, spoke length, chain length, and wheel-size comparison. Educational tools for dialling in your bike, not a substitute for your component makers’ specifications.
MTB Tire Pressure Calculator
Combine rider and bike weight, tire width, and terrain into a recommended front and rear pressure — a dialled-in starting point for grip and flat protection, split slightly toward the rear
Gear Ratio Calculator
Turn a chainring, cog, and wheel size into gear ratio, gear inches, development per pedal stroke, and speed at a chosen cadence — compare gearing across 26", 27.5", and 29" fairly
Suspension Sag Calculator
Get the exact sag in millimetres to measure on your fork and shock from their travel and your target percentage, plus a rough starting air pressure to fine-tune from
Spoke Length Calculator
Solve the wheelbuilding triangle from rim ERD, hub flange PCD and offset, spoke count, and cross pattern — with separate drive- and non-drive-side lengths for a dished wheel
Chain Length Calculator
Use the standard shop formula to size a chain from chainstay length and your largest chainring and cog — the shortest chain that still reaches the big-big combination, in links
Wheel Size Converter
Compare 26", 27.5", and 29" wheels on real outer diameter and rollout at your tire width, and see the gearing factor to keep gear inches constant when you change wheel size