If it is smooth then it will glaze the pads...tool harden if you will. If there is any slight ridging it will mean that the pads have to wear into the groves before you get full pad contact.asteffes said:I really do not understand why people insist on turning rotors for every brake job. I ran the same rotors on a track-driven car until they were worn past the factory-spec limit. They endured countless heat-cool cycles without warping, cracking or any other problems.
I use to not turn my rotors either. Once I swapped to new rotors when they were grooved to the point I felt they needed turning and the shop told me they were too far gone. MUCH better braking It convinced me it was worth the expense....Now it is true that you can almost buy a new Chinese rotor from Auto zone for older vehicles for what turning the rotor costs. I actually just buy new rotors and keep the old ones and turn them for them for the next brake job if I keep the vehicle long enough. Buddy turns them for free at his shop. :ylsmoke:
My Tow vehicle is BRUTAL on rotors. The had warped and made so much heat it warped the steel rims. Dealing with a combined weight of 12k if I am towing my truck thats understandable.