Brake pad

Brake pads are an important part of braking systems for all types of vehicles that are equipped with disc brakes. Brake pads are steel backing plates with friction material bound to the surface facing the brake disk.

Function

Brake pads convert the kinetic energy of the car to thermal energy by friction. When a brake pad is heated up by coming into contact with either a drum or rotor, it starts to transfer small amounts of friction material to the disc or pad (that is the reason a brake disk has a dull grey). The brake rotor and disk (both now with friction material on), will then "stick" to each other to provide stopping power. The friction of the pad against the disk is however responsible for the majority of stopping power.

In disc brake applications, there are usually two brake pads per disc rotor, held in place and actuated by a caliper affixed to a wheel hub or suspension upright.

Types

There are numerous types of brake pads, depending on the intended use of the vehicle, from very soft and aggressive (such as racing applications) and harder, more durable and less aggressive compounds. Most vehicle manufacturers recommend a specific compound of brake pad for their vehicle, but compounds can be changed (by either buying a different make of pad or upgrading to a performance pad in a manufacturer's range) according to personal tastes and driving styles. Care must always be taken when fitting non standard brake pads, as operating temperature ranges may vary, such as performance pads not braking efficiently when cold or standard pads fading under hard driving. In cars that suffer from excessive brake fade, the problem can be minimized, by installing better quality and more aggressive brake pads.

Materials

Asbestos was widely used in pads for its heat resistance, but due to health risks, it has now been replaced by aramid fibres.

See also

• Aramid
• Twaron
• composites
• Brake lining
• Brake shoe

External links

• The Brake Bible
• RockAuto.comBrake pad retailer & part number/vehicle application look up

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