Some Investigations on the Wobble Mode of a Bicycle

Wheel shimmy and wobble are well known dynamic phenomena at automobiles, aeroplanes and motorcycles. This eigenmode excites in particular oscillations of the wheel about the steering axis, and it is no surprise, that unstable bicycle wobble is perceived unpleasant or may be dangerous, if not controlled by the rider in time. Basic research on wobble at motorcycles within the last decades has revealed a better understand-ing of reasons for the sudden onset of wobble, and the complex relations between parameters affecting wobble have been identified. These fundamental findings have been transferred to bicy-cles. As mass balances and inertial properties, rider influence and lateral compliances of tyre and frame do differ at bicycle and motorcycle, approved models to represent wobble at motorcycles have to prove themselves, when applied at bicycles. For that purpose numeric results are compared with measurements at test runs, and parametric influences on the stability of the wobble mode at bicycles have been evolved. All numeric analysis and measurements are based on a specific test bicycle equipped with a steering angle sensor, wheel-speed sensor, GPS and a 3-axis accelerometer and angular velocity gyroscopic sensor