I've wondered why motorcycles can lean harder into turns than road bikes. I've went through the formulas and the only different variable I've found was tire traction. Is that really so? To me it does not explain the radical lean angle differences between Motorcycles and Road bikes.

If the tire alone was at fault, they could make the road bike tire stickier, softer (I don't really know much about tires) and we would all lean into corners at 60 degree angles.

  • $\begingroup$ You haven't shown that both these examples illustrate the limit. Quite likely they both don't, so the whole implied premise of your question is flawed. $\endgroup$ Commented May 27, 2017 at 13:09
  • $\begingroup$ It is believed that 45 degrees is the lean angle limit for road bikes and I have yet to meet somebody that actually did that. Since the pictures were of no relevance to the actual question I have removed them. Fact is a Road bike cannot lean 68 degrees into a turn like a motorcycle. $\endgroup$
    – AzulShiva
    Commented May 27, 2017 at 13:15
  • $\begingroup$ Motorcycles go faster than bicycles, but turn about as sharply. This is why they have to lean farther. $\endgroup$
    – mmesser314
    Commented May 27, 2017 at 13:37

1 Answer 1


As far as physics is concerned, there is no difference between the motorcycle and the road bike. As you suspect, the maximum lean angle $\alpha$ is set by the coefficient of friction $\mu$ :
So the main practical difference is the grip of tyres at large angles. Tyres on motorcycles are designed for high acceleration and taking bends at high speed, so they have high grip and are broad and thick. Tyres on road bikes are designed for efficiency : so they have low weight, lower grip, and are narrow and thin.

Another practical difference is speed. With a powerful engine capable of sustaining much higher speeds, motorcycles can lean into bends of much larger radius. Human-powered road bikes can only lean in for sharper bends.

Reference : http://www.stevemunden.com/leanangle.html


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