Is there any such thing as a 'warped' brake disc? Many people will tell you there is, but take a closer look and you might just find that it is just another myth. A widely believed myth, but a myth none the less.
EBC Brakes clearly state that a brake disc or rotor cannot warp:
Uneducated people still say “My rotors are warped”. Well the engineering facts are rotors do not warp, they are made of cast iron, they are very tough and can be run to red heat and cooled time after time and they will not distort, we do this day in day out on our dynos in the EBC lab. source: http://ebcbrakes.com/product/3gd-sport-rotors/
StopTech technicians state the following:
In more than 40 years of professional racing, including the Shelby/Ford GT 40s – one of the most intense brake development program in history - I have never seen a warped brake disc. source: http://www.stoptech.com/technical-support/technical-white-papers/-warped-brake-disc-and-other-myths
So why do some discs seem like they have warped? The technicians at StopTech state the following:
In fact every case of "warped brake disc" that I have investigated, whether on a racing car or a street car, has turned out to be friction pad material transferred unevenly to the surface of the disc.
Thats where brake disc skimming can make a big difference. On-wheel disc skimming takes a very thin layer off the disc and matches the disc exactly to the wheel, resulting in a flat and accurate braking surface. No new discs, improved performance, improved braking and significant cast savings - that a win-win-win-WIN situation!