Need Help in Shanghai

[Handoogies]

Hi, I am posting this for a tracking friend:

He has a 997tt which about a month ago, he noticed that when under heavy braking in a straight line(ABS engaging) the car would feel as if it were swaying left and right. Now that problem is compounded with HEAVY jarring and shaking of entire cabin when speeds exceed 100mph, more shaking the faster he goes. He recently switched out a rear tyre without swapping both out, and I told him that could be the issue but he thinks its something far more serious. We track our cars and he is known to go a bit heavy on his car. Anyone with any ideas of what could be the problem? We have a track day this Saturday and he has no time to bring it into a shop before then.

[Loren]

:welcome:

Tires can do it that is why Porsche says always change both ties on the same axle.

I would start by getting some know good tires (i.e. swap with a friend) and try some stops. Obviously if it goes away - you've found your problem.