Why rotors warp

Brake rotors warp because the temper in one area of the rotor is different then the rest of the rotor. When subjected to thermal stress (or mechanical stress from unevenly or over-tightened lug nuts) the rotor warps. Turning or truing the rotor will alleviate warps that exist when the rotor is cold, but will not solve the problem when hot, the uneven temper still exists within the substrate. The only permanent solution is to replace the rotor. The manufacturing cost of brake rotors is mainly related to the length of the cool down time during the casting process. Cheap rotors are removed from the sand molds too soon and generally develop uneven temper. Expensive rotors are left overnight to cool in the molds, allowing them to temper very evenly. This extra time in the molds eats up the foundry's production capacity, so the parts are more expensive.

How do you know if you're getting good rotors? That's a tough one. Several aftermarket rotors are available for the SHO, the SHO Shop and Donelson Motorsports come to mind, these guys have better quality rotors that are available cross-drilled or not, Donelson claims that theirs are preheated. Preheating, performed properly, will anneal-out the uneven temper in the casting.

Lug nut torque

Rotor seasoning, why and how

No, this isn't done with salt and pepper, seasoning is how you prepare a new rotor for service. Seasoning will bake out the oils and solvents used to manufacture the rotor and will also even the temper of the rotor, increasing its life, improving its wear characteristics, and lessening its tendency to warp. Seasoning is performed by GENTLY heat cycling the rotors several times. For street cars, this is best done over a 2 or 3 day period. Drive the car normally, avoid panic stops, get the brakes warm but not smoking hot. Allow the brakes to cool to ambient temp to complete each heat cycle. Avoid holding the brake pedal down or setting the parking brake when the rotors are hot, this promotes uneven cooling of the rotor surface which can lead to uneven tempering.

Again, the key phrase here is 'gentle heat cycling'. If you go to the trouble and expense to put on new pads and rotors and then go out and immediately HAMMER the brakes, you're wasting your time and money.

Now that the rotors are seasoned, the brake pads, if they are new, can be bedded.

Bedding my brake pads, what will my spouse think?

Find a location where you can accelerate up to 60 MPH, brake heavily to 5 MPH, and then repeat this cycle several times (usually 5 to 7) until the brakes fade significantly. If done properly, the brakes will smell and may smoke somewhat, that's why bedding is often referred to as "letting the smoke out". Now, drive for 10 minutes or so, at highway speed, utilizing as little braking as possible. Park the car overnight, allowing the brakes to cool to ambient, again, don't set the parking brake, especially if you've put new pads or rotors on the rear.

BTW, if you bought cheap rotors, with poor temper, they will probably warp during pad bedding, so sorry.

Some pads come pre-burnished, the manufacturer has baked the pad to drive off the organics and cure the bonding agents. These pads don't need to be bedded, but it won't hurt anything if you do it anyway, bedding also helps to carbon-load the rotor surface, improving brake effectiveness.

Note about carbon-loading: if you change from carbon-compounded brake pads to pads with no carbon content, you'll need to change the rotors. The surface carbon loading on the rotors can make non-carbon content pads somewhat ineffective, i.e. NO STINKIN' BRAKES!