Brake discs/δισκόπλακες for cars are always made from cast iron. Cast iron has excellent heat conduction properties meaning sudden increases in temperature on one part of the brake disc is quickly conducted to the whole of the brake disc.
This fast conduction of heat allows the whole brake disc to have a relatively even temperature.
This has a number of benefits
The first is that iron discs are extremely resistant to warping. Warping occurs when a part of a metal expands faster than the metal next to it leading to kinks and bends in the metal. These kinks or bend are not visible to the human eye.
The second is that cast iron brake disc can easily withstand rapid changing in temperatures without warping. For example running through water when the brakes are hot will not effect the thickness of the brake disc.
Cast iron brake discs/δισκόπλακες found on cars are now so well developed that any vibration through the brake disc is probably down to excess build up of pad material on the brake discs service as opposed to any difference in the thickness of the metal itself.
This build of brake pad/τακάκια
material can sometimes be visible to the naked eye as the outline of the brake pad can be seen on the disc.
Brake discs which have been effected in this way can be “skimmed” to clean any excess material off the disc. EBC now recommend this as the cure to any brake vibration issues and will not entertain any warranty issues until the brake discs/δισκόπλακες have been skimmed on a Pro-Lathe.
Uneven build up of pad material on the brake discs can be caused by two main things
The first is pad overheating. Some low quality or abused brake pads can actually start to melt and leave deposits on the brake disc.
The most common reason for brake vibration however is much more simple. After a big stop from high speed the brake will build up a lot of heat. If the car is then held at a standstill with the foot brake, the brake discs/δισκόπλακες and the pads/τακάκια can attach themselves. When the car moves again a small layer of brake pad material is left on the brake disc.
The golden rule for avoiding any brake issues is first of all to ensure the brake pads you use are high quality and second to make sure that when you car is at a standstill, at traffic lights for example, you do not leave your foot resting on the brakes. If you need to stop the car use the handbrake. Around town this practice is not necessary as there will not be a lot of heat in the braking system but if you have stopped from high speed for a traffic light it is recommended that you use the hand brake instead of the foot brake.
At Street & Circuit we offer standard replacement brake discs/δισκόπλακες from Brembo, Bosch, Valeo and Bradi. We also offer performance brake discs which have grooves and/or dimples from EBC, Brembo and Tarox.
In our opinion performance brake discs/diskoplakes do not give a big an improvement as brake pads. Performance brake discs/diskoplakes are for those drivers who want to extract every ounce of performance from their brake system without going to the next step of fitting a big brake kit.
If you would like any advice regarding your choice of brake discs/diskoplakes please call us