Countermeasure and Analysis of Squeal in Bicycle Disk Brakes

This paper deals with the occurrence mechanism of the squeal phenomena generated in a new type of bicycle disk brake unit and its countermeasure experimentally and analytically. It was made clear that squeal was in-plane vibration in the direction of disk surface with frequency 650 Hz caused by frictional characteristics with negative slope with respect to the relative velocity, and was generated in the vibration system including brake unit and spokes, in the same manner of old type of disk brake unit. The countermeasure against squeal by using a dynamic absorber was conducted. The simple analytical model of the bicycle disk brake system was set up. Some features of squeal phenomena and the optimal design of dynamic absorber for quenching squeal were made clear analytically and it was confirmed that the analytical results agreed well with the experimental ones.