very bad vibration when rotors are hot
 

Hello,

My z has about 40k miles on it, it brakes perfectly fine on normal day to day driving. However, when I drive more aggressively and brake more often, the steering wheel starts to vibrate very very badly. it seems like this vibration only occurs when the rotors are up to a certain temperature...
Does anyone know what the problem is? i thought warped rotors vibrate all the time no matter the temperature is.

thanks in advance!

Could be caused by "hot-spots" on the rotors - if you get the rotors really hot (track day type usage) and just park up and leave the car in one spot, then the rotor area under the pad cools vastly more slowly than the rest of the rotor, which work-hardens that part of the rotor friction-disc.

In ordinary motoring, it is not significant, but when the rotor gets hot, like when you really lean on the brakes, you get differential friction between the two segments of the rotor which translates as a steering shudder (eg: "grip a bit, grip a lot, grip a bit, grip a lot")

If this is the case, your rotors are going to be toast.

You might be able to see (on a cold rotor) a "bruise" on the rotor disc where it was "heat-treated".

RB

... Um...
Is it possible you feel it because you're braking from a higher speed?

Slightly warped rotors do not vibrate at any speed, they'll only vibrate at high speed.