Automotive friction materials evolution during the past decade

Until the late 1960s, the U.S. passenger car and light truck automotive market used drum brakes on all four wheels and organic brake linings. In the late 1960s and early 1970s there was a transition to disc front-drum rear brake systems. Following these changes, which were still not fully settled, the past decade produced even more drastic changes. Beginning in the mid1970s, three important new requirements were imposed on the automotive industry: the Federal braking regulations, the need to eliminate asbestos from friction materials, and the conversion of the heavy vehicles to more energy-efficient lighter and smaller front wheel drive vehicles. These changes necessitated development of a new generation of friction materials. The changes in brake system configurations and the evolution of new friction materials which have occurred during the past decade or so to meet these new requirements are described in this paper.