The rotors aren't really warped in the true sense of the word. There are hot spots being created in the metal which causes the formation of Cementite.

"Cast iron is an alloy of iron and silicon in solution interspersed with particles of carbon. At elevated temperatures, inclusions of carbides begin to form in the matrix. In the case of the brake disk, any uneven deposits - standing proud of the disc surface - become hotter than the surrounding metal. Every time that the leading edge of one of the deposits rotates into contact with the pad, the local temperature increases. When this local temperature reaches around 1200 or 1300 degrees F. the cast iron under the deposit begins to transform into cementite (an iron carbide in which three atoms of iron combine with one atom of carbon). Cementite is very hard, very abrasive and is a poor heat sink. If severe use continues the system will enter a self-defeating spiral - the amount and depth of the cementite increases with increasing temperature and so does the brake roughness."
StopTech : Balanced Brake Upgrades

Once hot spots/cementite has formed (aka "black spotting") the rotor is cannot be "cured" of the problem (by turning them) and new rotors are necessary.

I agree that the pads are probably the major factor in causing this problem, but the quality of the rotor plays a big part too.

The problem everyone complains about when they use the term warped rotors, brake shudder, pulsing brakes, etc almost always is not due to a warped rotor.

The definition of warp is a twist or curve that has developed in something originally flat or straight. That's not what's happening to the rotor when it comes to the problems described here. The problem is hot spots or black spotting which is the formation of cementite. No amount of turning on a lathe can eliminate this problem.

Here is another excerpt by Carroll Smith in his article "The 'Warped' Brake Disc and Other Myths of the Braking System"

"The term "warped brake disc" has been in common use in motor racing for decades. When a driver reports a vibration under hard braking, inexperienced crews, after checking for (and not finding) cracks often attribute the vibration to "warped discs". They then measure the disc thickness in various places, find significant variation and the diagnosis is cast in stone.

When disc brakes for high performance cars arrived on the scene we began to hear of "warped brake discs" on road going cars, with the same analyses and diagnoses. Typically, the discs are resurfaced to cure the problem and, equally typically, after a relatively short time the roughness or vibration comes back. Brake roughness has caused a significant number of cars to be bought back by their manufacturers under the "lemon laws". This has been going on for decades now - and, like most things that we have cast in stone, the diagnoses are wrong.

With one qualifier, presuming that the hub and wheel flange are flat and in good condition and that the wheel bolts or hat mounting hardware is in good condition, installed correctly and tightened uniformly and in the correct order to the recommended torque specification, in more than 40 years of professional racing, including the Shelby/Ford GT 40s – one of the most intense brake development program in history - I have never seen a warped brake disc. I have seen lots of cracked discs, (FIGURE 1) discs that had turned into shallow cones at operating temperature because they were mounted rigidly to their attachment bells or top hats, (FIGURE 2) a few where the friction surface had collapsed in the area between straight radial interior vanes, (FIGURE 3) and an untold number of discs with pad material unevenly deposited on the friction surfaces - sometimes visible and more often not. (FIGURE 4)

In fact every case of "warped brake disc" that I have investigated, whether on a racing car or a street car, has turned out to be friction pad material transferred unevenly to the surface of the disc. This uneven deposition results in thickness variation (TV) or run-out due to hot spotting that occurred at elevated temperatures."
StopTech : Balanced Brake Upgrades

There's even information about Cementite found on EBC's web page.

Hot spots, black spotting, cementite, carbite, hard spots, whatever you wanna call it, it cannot be fixed by turning the rotor. These spots are what causes the brake shimmy, pulsation, warped feeling that people complain about in the "warped rotor" threads.

Proper torque procedure is also brought up when "warped" rotors are talked about. Using a two-step method and torquing the rotors down (using a star pattern) to 80ft lbs first, then to 160ft lbs has been recommended for years as a way to eliminate a situation that may allow warpage to occur.

My prefered rotors are either Raybestos R-300 High Performance; S-Groove Technology, or the AC Delco Professional Gold S-Groove series:

More Information for RAYBESTOS 980784PER

More Information for ACDELCO 18A2738SD

They are the same manufacturer and same material. Have had good luck with with these after "warping" the OEMs.

Geez, that was three years ago. Thaks for clarifying ;-)

Sometimes there is a need to dispel BS posts. Parts guys at a dealer don't know squat. They just throw parts at things.

I just replaced the alternator on our 2014 SR5 at 319K miles. Lithia Toyota in Missoula said the alternator would cost $580, be there in 2 days and since it was a reman, would require return of the old alternator as a core. Googled Toyota parts online and the alternator was $326 and no core charge (new Denso unit).

Well, it's good that you're looking for old inaccurate posts to dispel. I don't want to be the unwitting propagator of misinformation. But don't disrespect parts guys you never met. I've worked with this particular guy for 40 years. He's saved me thousands of dollars during that time.

It showed up on my feed today and I responded. I wasn’t looking for it.