Measuring the Mechanical Properties of Bicycle Tyres to Help Predict and Minimize Wobble for Enhanced Safety

Abstract

Wobble, also known as speed wobble or shimmy, and the hazard it can cause to cyclists, is a well-known behavior of some bicycles. lt is a relatively high-frequency oscillation, 4-10 Hz. of the front fork and wheel assembly about the steering axis, and it can result in loss of control if left unaddressed. The importance of tyre mechanical properties, specifically conering stiffness, to the wobble motion of bicycles has been shown. Some tyres can make a bicycle more likely to wobble, while others can make the same bicycle less likely to wobble. There are only a few facilities in the world, however, capable of measuring these properties of bicycle tyres, and facilities for testing motorcycle and automobile tyres are not designed to work with bicycle wheels and/or are prohibitively expensive to use. We introduce and characterize an inexpensive, table-top device for measuring the necessary mechanical properties of bicycle tyres.