Heat is the enemy, as the big dog says, but rotors can take plenty of heat and stay true a and flat. Quite a few years ago now, I went into my LM dealer complaining about rotor warpage on my 1993 Merc GM. The SM told me this story, and I walked away from that garage shaking my head in disbelief, chaulking it up to yet another BS story from a dealership. A few years later, I began to believe that story and am now convinced of its truth. OK, the story, without further BS: This guy (the SM) said that the rotors were becoming warped due to un-even heat dissipation, caused by keeping the brakes clamped onto the same part of the rotor surface throughout a controlled stop, like at the red light. On your approach to a red light, you are running on your brakes to slow down and stop. Then, you set there with the brakes holding the car while you wait at the light, and the rest of the rotor cools down, while your brake pads hold the rotor still and keep the heat concentrated in that spot. For this, we can thank, in part, our wonderful automatic transmissions and torque convertors, for passing along the forward crawling power, which necessitates our standing on the brakes whenever the car is in drive and stopped. Whenever I am stopped now with an automatic (which isn't often since 1994), I allow enough room for the car to be stopped, inched forward a foot or so, and repeated for the minute or so that the lights are red. I give it around 10-15 seconds in any one spot before rotating the rotor out of the hot brake pads.
On the other hand, on my manual-equipped cars, there have been days where I put the car in the garage after a commute through the twisties, and actually smelled smoke coming out of the front pads and rotors, and have yet to warp a rotor on either my old Peugeot Mi16 (1994-2001) or my LS, 2001-present, both manually equipped cars with very good binders from the factory. Both cars are equipped with hand brakes for parking, which I use at stop lights if the ground is not level.
Anyone else ever heard of the un-even brake heat dissipation theory?
Mike