Influence of rider movement

Influence of rider movement

Changing direction by turning the handlebar influences the lean of a motorcycle by a factor proportional to the square of the speed (curve on chart above). One must subtract the contrary influence of fork trail, which explains its negative value at zero speed. It is an essential variable in the controlled changing of direction of a motorcycle. The influence of gyroscopic effect on the lean of a motorcycle is proportional to speed (sloping straight line on chart), the degree of rotation of the handlebar and the moment of inertia of the wheel. As demonstrated by the experience of British engineer David Jones in the 1970s, it is possible to control a motorcycle on which gyroscopic effect has been nulllified.Lateral movement of the rider influences lean of a motorcycle to a constant extent (dashed line on chart). This influence is not related to speed and is not significant.