Wobble of a racing bicycle with a rider hands on and hands off the handlebar

Abstract

So far fundamental papers on the understanding of the wobble mode at motorcycles have been published, but in contrast, little research has been published on the wobble mode at bicycles. Wobble denotes a characteristic unstable oscillatory mode dominated by oscillations of the front wheel about the steering axis. The wobble mode of a trekking bicycle at low speeds has already been analysed, where no influence of the rider's hands on the steering system is taken into account. The wobble mode of a racing bicycle at higher speeds has not been addressed in more detail so far. The paper points out the difference between a trekking bicycle and a racing bicycle in particular with respect to the wobble mode. Different geometry, mass and stiffness properties of both types of bicycles and different characteristic positions of the rider are considered. As the wobble at racing bicycles often occurs at high speeds, when riding down a grade with hands on a dropped handlebar, a passive rider model, that takes into account the movement of the rider's arms, is presented.

Keywords:

• bicycle
• wobble
• rider model
• stability analysis

The authors thank Gianantonio Magnani, the first author of [13] and rider of the above ‘wobble prone’ bicycle, for the measured data of his scary downhill rides at 65  km/ h exposed to harmful steering oscillations. He initiated to extend our research on the wobble mode of riding a trekking bicycle hands-off to racing bicycles. As a consequence, the above rider model for hands-on downhill rides at high speeds has been introduced. Based on several wobble experiences on his racing bicycle, alternative modelling approaches are now under investigation.