Posted by Ben on March 12, 19100 at 11:50:45:
I'm hearing many complain about rotor warpage and at some very low milage numbers.
One major contributor is improper wheel lug nut torque procedure. It sets up uneven stresses in the whole assembly and the heat cycling & braking torque build on top of that to warp the rotors. How fast the heat raise & the ultimate temp reached are other major factors.
To remount a wheel/tire to the vehicle you should first hand tighten them all (includes wheel locks).
Then torque them to 50%-60% of factory number and use cris-cross pattern.
Then lower vehicle weight on the wheel and tighten to 70%-80% using cris-cross pattern.
Finally tighten to 100% factory torque number using cris-cross pattern.
Retorque after a few hundred miles to factory torque number using cris-cross pattern.
With the high performance friction material and the weight of our Suburbans, think the rotor tempuratures higher than most passenger vehicles, so we see more wraped rotors. I've wittnessed many wheel/tire installers spin on the lug nuts in non-cris-cross pattern and to the full factory torque number with an air wrench. They will use a torque wrench, but have also double checked at home and find that it's OVER torqued many times.
Probably okay wiht the family sedan, but with performance vehicles (our Sub's qualify due to the severity of service the front rotors see) and the higher temps, there are many more warped rotors because of this sloppy installation.
Just my $0.02.
-Ben