Motorcycle Lean Angle Calculator (Speed & Corner Radius)

How it works

lean angle θ = arctan(v² ÷ (g × r)) · lateral acceleration = v² ÷ (g × r) in g · grip needed μ ≥ tan θ · top speed at lean limit = √(g × r × tan θmax) · v in m/s, r in m, g = 9.81 m/s²

In a steady turn the bike leans until gravity and the cornering (centripetal) force balance, so the lean angle depends only on speed and radius — not on the weight of bike or rider. The tangent of the lean angle equals the lateral acceleration in g, which is also the minimum friction the tyres must supply. Real bikes lean a few degrees more than this ideal figure because the contact patch moves to the side of a wide tyre, and less if the rider hangs off the inside.

Worked example

At 60 km/h (16.7 m/s) on a corner with a 50 m radius: v² ÷ (g × r) = 277.8 ÷ (9.81 × 50) = 0.57 g, so the lean angle is arctan(0.57) = 29.5°. With a 45° lean limit the same corner could be taken at about 80 km/h.

Sources: Bicycle and motorcycle dynamics — lean angle in a steady turn · HyperPhysics — Centripetal force

Frequently asked questions