these are normal signs of either loose or worn-out ball joints and/or wheel bearings.
Then why does it go away when you replace the rotors?
It may easily be warped brake rotors
When brake rotors are warped, they shudder all the time, not just when they are very hot.
bent or even loose wheels
Then why does it go away when you replace the rotors?
it is so important to torque down the wheel's lug nuts evenly, warped brake rotors are commonly caused by improper torquing.
Except that these aren't warped (see above) and they happen even when the lug nuts are torqued properly (in my case, using a torque wrench that has been calibrated and found to be accurate).
Brake shudder is a fairly common problem in NSX's. I experienced it over and over for a long time. It would go away when I replaced the rotors. After a couple of track events, it would start to re-appear. After a couple more, it would be so severe that I would replace the rotors and start the cycle over again.
If this only happens to you once, I would just replace the rotors. If it happens again - likely only if you track your car - then I would consider some of the other steps I took (high-performance pads, high-performance rotors, high-performance fluid, and cooling ducts).
[This message has been edited by nsxtasy (edited 28 February 2002).]
