[Grubby]

Warped rotor vs uneven pad deposits on the rotors is debated in the auto industry. I am not sure what the answer is.

I have measured numerous rotors for runout and thickness when pulsation was felt (50+ rotors over 30 years). My personal observations are;

1. used auto rotors are always below minimum thickness;
2. auto rotors are right at minimum when new;
3. light duty truck rotors are above minimum, but too close to minimum to bother turning when they pulsate
4. when rotors pulsate, I have noted typical runout of .003" to .005" total. That could be material build up or warped.
5. new rotors with measured runout of 0" certainly cures the issue
6. turning a rotor that is at minimum thickness to remove pad material build up would yield a rotor that is below minimum

I will continue to install new quality rotors when pulsation is felt. Good quality rotors typically have runout of 0" and can be purchased for about $50.

John