JNavas wrote:Rotors do not "warp", a common misconception. What happens is uneven wear, usually caused by improper installation or improper turning. Proper rotor installation is critical.MrAl wrote:There is a way to check the rotors for warping, by checking the runout. A dial indicator is mounted somewhere while the rotor is turned by hand, and the runout has to meet a certain spec. If it meets the spec then it is not considered warped, but if it does not meet the spec then it is considered warped. You might have to check for your model/year on the spec. I dont think it's too hard to do this but you have to remove the wheel and have a dial indicator with mounting arm.
Hello,
An older thread but i havent been around for a while so i am replying a bit late.
I have learned a lot more about this since then. The idea with 'warping' is that it was believed that the high temperatures involved with braking causes the rotor plate to heat up and thus warp due to the heat. But even with the most intense driving, i dont think this can really happen.
However, 'rotor warping' is a pseudonym which has been used, and more importantly understood, by the general public as being a change in the surface symmetricalness of the rotor plate without really specifying why that is, or rather providing a fictitious reason. This happens quite a bit in language where a term that is simpler to remember or understand finds preference among speakers of the language. The main point being that it is understood by the majority of speakers.
However, 'runout' is sort of just another pseudonym too, because it just declares that the surface or surfaces is/are problematic also without providing a reason behind it. It's no doubt a better term i agree, because there is no fiction involved, just an after the fact representation of what must have happened previously that we dont feel like explaining every time we talk about it.
I do believe now that 'warping' is an attempt at explaining this phenomenon but because it is incorrect that means it is misleading. The new hearer of this will believe that the heat caused the plate to bend or curl.
From what i understand now, the most common reason for the so called warping is uneven transfer of material between the brake pad and the brake rotor disc surface. The transfer of material could go back and forth over time, and if the material that gets left on the disc rotor surface is not uniform, it will start to make noise and cause a pulsation on braking.
I will be looking into this more too possibly in the future.