Motorcycle Calculators

Gearing, chain, suspension, tyres and range. 14 calculators for riders who do their own spannering.

Sprocket ratio is the cheapest change most bikes accept and the one most often done backwards. Going up one tooth at the front is roughly equivalent to going down three at the rear, and it lengthens the gearing. Riders wanting quicker acceleration usually want the opposite: down one at the front or up two or three at the rear. The page shows the resulting speed at redline in each gear, which is the number that tells you whether you have just given up your motorway cruising.

Chain slack is a safety item, and the spec is measured with the bike on its wheels rather than on a stand. A chain adjusted tight on a paddock stand goes drum-tight when the suspension compresses through its arc, and that destroys output shaft bearings. The page states the measuring condition alongside the range, because half of the service manuals that give a figure omit it.

Lean angle and cornering pages are physics, not advice. They show what the tyre and geometry allow in ideal conditions, which is not what a public road in the rain allows.