Brake discs, known more commonly as brake rotors, are the most common devices found on a modern vehicle. The brake disc is a circular device that is commonly attached onto the end of the vehicle’s axle, just before the actual wheel. The brake caliper fits over the disc via a special bracket, allowing the piston within the caliper to grasp the disc with specially-designed pads, thus slowing the vehicle down. An integral part of the vehicle’s braking system, the average brake disc helps stop a vehicle with a greater amount of efficiency and performance than brake drums.
Brake discs are usually made from a single solid cast iron piece. Ventilated brake discs feature vanes or slots in between the two solid contact surfaces. Some performance-oriented brakes offer shallow channels machined into the disc face for removing gas and dust, while others are cross-drilled for improved heat dissipation. In the vast majority of vehicle applications, brake discs are used on the front wheels, where the vast majority of the vehicle’s weight ends up due to weight transference upon braking. This allows most automotive manufacturers to cut costs by featuring cheaper rear drums on the rear wheels. Racing vehicles commonly use brake discs made from carbon fiber or other composite materials for enhanced performance and lower weight.
Brake discs aren’t just limited to use on automobiles. Most modern motorcycles use disc brakes to facilitate improved stopping performance. A growing number of bicyclists prefer brake discs to other forms of braking, thanks to their predictability in performance.