Disc thickness variation compensation

A vehicle braking system of the type having individually controlled brakes with respective angularly fixed and rotatable friction surfaces urged into contact by an operator initiated braking force for each of a plurality of rotatable vehicle wheels has braking torque variations within a wheel revolution alleviated for each wheel by sensing variations in braking force as a function of wheel angular position during a complete vehicle wheel revolution and initiating a reduction in braking force during a subsequent wheel revolution prior to the wheel reaching an angular position at which an increase in braking force was sensed during a previous wheel revolution. A particular wheel angular position may be identified as a reference position and data indicative of the sensed variations stored as a function of wheel angular position relative to the reference position. This stored data is then utilizing to determine the angular position at which braking force reduction is initiated. Identification of a reference position may be directly done by sensing an angular anomaly generated by the wheel speed sensor, or indirectly by storing data indicative of the sensed variations, analyzing the stored data to identify any established patterns within the data, and identifying a particular wheel angular position as a reference position based on an identified repetitive pattern.