Motorcycle Lean Angle Calculator

Lean angle is the angle between the motorcycle and the vertical, measured when cornering. Understanding lean angle helps riders appreciate the physics of cornering and the limits of tyre grip.

The physics of cornering on a motorcycle involves balancing gravity (pulling the bike down) against centrifugal force (pushing the bike outward). At equilibrium, the lean angle satisfies:

tan(θ) = v² / (g × r)

Where:

• θ = lean angle from vertical (degrees)
• v = speed (m/s)
• g = 9.81 m/s² (gravitational acceleration)
• r = corner radius (metres)

This can be rearranged as: θ = atan(v² / (g × r))

Reference lean angles:

• 15 to 25°: gentle sweeping bends, confident road riding
• 30 to 40°: spirited road riding, moderate corners
• 45°: significant lean, and where most road tyres start to run out
• 50 to 55°: sport riding on good surfaces with sport tyres
• 60° and up: MotoGP territory. Racing tyres, perfectly clean surfaces, and enormous skill
• Maximum theoretical: about 64°, limited by the footpeg or exhaust touching down and by the tyre sidewall

Tyre grip and safety margin: road tyres typically offer a coefficient of friction of 0.8 to 1.0 on clean dry tarmac, which corresponds to a maximum lean of about 38 to 45°. Sport tyres on a track can reach 55 to 62°. Wet roads cut grip by 30 to 50%, so safe lean angles drop a long way.

The cornering speed calculator works the same physics from the other end: give it a friction coefficient and it returns the speed, with lean angle falling out as atan(μ). The two pages agree, which is worth knowing because it means lean angle is never something you choose. The corner and the speed decide it, and the bike follows.

Important: this gives the theoretical lean angle in ideal conditions. Always ride with a margin. Road debris, surface changes, and mid-corner surprises all want grip you have not already spent.