From a youth’s first legal rollout to the gear you grind up the last climb.
Not just youth gear any more. Check rollout and legality for any category in a tap, read the whole gear table at a glance, lay out your own chainrings and cassette with the jumps between each gear, and for a long climb set the gradient and your power to see the cadence you'd actually turn. Pick the gear that lets you spin, not strain. Saddle up.
Rollout & Legality
One gear, every number. Check a single chainring and sprocket for rollout, gear inches, ratio, gain ratio and speed, and see at a glance whether it is legal for a category, with the gear you would need to make it so.
Gear Matrix
A grid across chainrings and sprockets, shaded so similar gears share a hue. Switch between rollout, gear inches, ratio and speed, and pick a category to grey out anything over the limit.
My Setup
Your actual drivetrain, analysed. Enter your chainrings and full cassette and it lays out every gear with rollout and speed, then tells you the range, the jump between gears and any near-duplicates worth knowing about.
Climbing Gears
What gear for the hill. Give the gradient, your weight on the bike and the power you expect to hold, and it works out how fast you will go up, then the cadence each sprocket would turn at that speed, so you can see which gear keeps you spinning rather than grinding.
Compare Setups
Two drivetrains, side by side. Useful for 1x against 2x, or two cassettes, on range, usable gears, the size of the jumps and the top and bottom speed.
Current rollout limits and sources
Youth C, Under 12: max 6.34 m
Youth B, Under 14: max 6.73 m
Youth A, Under 16: max 7.18 m
Junior, Under 18: max 7.93 m
Youth D and E: unrestricted
Time trial, cyclocross and MTB: no restriction
U9, U10, U11: max 5.52 m
U12, U13: max 5.76 m
U14, U15: max 6.48 m
U17 and up: unrestricted
British Triathlon (from 2026)
All youth and Tristar age groups: max 7.00 m