Brake linings are made of a relatively soft but wear-and-tear and heat-resistant material with a high coefficient of dynamic friction and also high coefficient of static friction. The linings are mounted to a solid metal structure using high-temperature adhesives or rivets. The complete assembly is then called a brake pad or brake shoe.
The dynamic friction coefficient "µ" for almost all of the brake pads is usually in the range of 0.35 to 0.42. In such a condition, a force of 1000 Newtons on the pad will give a resulting brake force close to 400 Newtons.
Some racing pads with a very high µ of 0.55 to 0.62 with excellent high-temperature properties are also available. These are high in iron content and they outperform other pads used with iron discs.