RTV - A Friction Material Designers View

Brake judder due to thickness variations around the brake rotor is a major concern in the automobile industry and, whilst many institutions are currently attempting to understand and address this problem, there is little published data on the subject. This review paper examines the probable causes of so called cold judder and describes the techniques used in evaluating rotor thickness variation (RTV). These vehicle- and dynamometer-based methods are then critically appraised and approaches to the alleviation of RTV are identified. Methodologies for enhancing friction materials are postulated and techniques are examined which may provide vehicle and brake manufacturers with data facilitating improvements to brake systems and vehicle components aimed at eliminating cold judder.