The smoothness on the surface of the Porsche disc brake rotors permits the friction involved in the stopping procedure on your vehicle to be created with no damage being inflicted on any of the braking components. On each of the brake rotors mounted on a Porsche, there are two flat disc-like surfaces where the brake pads make contact with them. By design, the brake pads are made out of a softer material than the brake rotors so that the friction created when the two braking components are being forced together simply slows the rotation of the wheels on your Porsche rather than destroys or disfigures the disc. The only byproduct of this action is that a small portion of the brake pads are converted to dust. On both sides of the flat surfaces of the Porsche disc brake rotors, covering a portion of the disc, you will find a brake caliper. This is the mechanical device that uses hydraulic pressure to apply the force that pushes the pads against the discs. When the braking system is properly maintained the disc brake rotors will last for the life of the vehicle. Most people have heard a vehicle making a grinding noise when its brakes are being applied. This is metal to metal contact from the brake rotors and the backing plate that the brake pads were mounted to. If this noise is heard on a Porsche, then the brake pads have worn out and the grinding noise is an indication that grooves are now being cut into the smooth surfaces of the discs on your vehicle. This will increase the price of the brake job that is required to keep the vehicle safe while on the road.