Abstract: The invention relates to an air flow test apparatus for determining the amount of air moving through vents in a turning ventilated rotor. The air flow test apparatus includes an elongated cylindrical shaft journalled for rotation in spaced apart bearing blocks mounted in a frame. A conventional belt drive couples the shaft to a variable speed motor for rotation. An adapter is mounted to the shaft and a work piece is mounted to the adapter end for rotation with the shaft. The work piece includes a hub secured to the adapter for receiving a plurality of different sized rotors, and a ventilated rotor mounted to the hub. The work piece may also include other vehicle components such as the caliper, a wheel, even an entire corner portion of a vehicle for simulation purposes. A pressure gauge is disposed adjacent the rotor, near the vents, to measure the air pressure near the turning rotor.

Abstract: A brake rotor includes a radially inner hub or hat section having a central mounting face for mounting the rotor on an associated drive member, with an outer friction portion extending from the cylindrical hat wall. The outer friction portion includes a pair of opposite, flat annular friction rings adapted to interface with associated friction members. The outer friction portion of the rotor further includes a core extending radially outwardly from the cylindrical hat wall of the hat section. A layer of a sound dampening material is secured between the pair of outer friction ring sections and the core. The rotor of the invention transmits less noise than conventional rotors.