brake discs

A brake disc is usually an iron (or carbon composite) disc that is attached to the suspension of a car, motorcycle or even bicycle and is gripped by brake pads held in a brake caliper. The friction between the brake disc and the pads is what brings the car to a halt. The brake disc has numerous advantages over the brake drum, because it dissipates heat quickly, giving strong and consistent braking performance. Disc brakes also give the driver more ‘feel’ at the pedal, allowing him or her to more easily modulate the pressure for a smooth stop. In higher-performance applications, a brake disc will actually comprise two discs attached side by side by various rotors. This, in effect, makes the disc ‘ventilated’ further helping cooling and performance. Brake discs are also commonplace on motorcycles, where they are drilled to improve wet-weather braking performance. Instead of the brake pad having to compress any water on the surface of the disc, which hampers stopping ability, the water is pushed into the holes on the disc, thereby allowing the brake pads to grip the disc as intended. As a way of avoiding the stresses associated with excess heat build-up during braking, some discs are sometime mounted almost loosely on to the hub via coarse splines. This loose mounting allows allows the disc to expand evenly with the heat, and stops it transferring too much heat to the hub on which it is mounted, which could cause a failure. Disc brake technology has advanced to the point where it is not only used on cars and motorcycles – pedal cycles now commonly have disc brakes as standard because these provide stronger and more consistent performance in adverse weather. Such braking systems are also light enough that they don’t impact on the overall performance of the bicycle.

What are the symptoms of a bad brake disc? Some common symptoms of bad rotors include vibration or pulsation in the steering wheel, high-pitched squealing noise when braking, shaking steering wheel, brake pedal pulsing, vehicle taking a long time to stop, loud bangs while braking, large edges on the outer part of the brake rotor, and scratch marks on the rotor.

Generally, brake discs should last more than 50,000 miles on average, but a number of factors affect the lifespan. If you keep them well maintained and drive sensibly, you may be able to get up to 80,000 miles out of one set.

Brake rotors of disc brakes rotate with the wheels, and brake pads, which are fitted to the brake calipers, clamp on these rotors to stop or decelerate the wheels. The brake pads pushing against the rotors generate friction, which transforms kinetic energy into a thermal energy.

A brake pad lies between the rotor and the caliper to reduce the level of friction from metal on metal. Over time, the pads need replacing. When a driver applies the brakes, they may hear a screeching sound, or the vehicle pulls to one sign. These are indications that the pads are worn.

The brake disc is an important component of the brake system. If the brake system is to be able to decelerate the vehicle in safety and comfort at all times – bringing it to a complete stop if necessary – the brake disc must combine with the brake pads to generate a brake torque (a brake force).

The brake disc is an important component of the brake system. If the brake system is to be able to decelerate the vehicle in safety and comfort at all times – bringing it to a complete stop if necessary – the brake disc must combine with the brake pads to generate a brake torque (a brake force).