strange 996tt issue

[niceguy]

Having had the wheel balancing done for all 4 wheels, I went for a test drive and the steering wheel vibration at 100kph was gone. But, sadly, it is now vibrating at 110kph or so. The strange thing is that after some spirited driving, the car vibrated more than it did normally and the vibration now seems to be shaking the whole car at 110kphph quite badly. Could this be an engine or gearbox or suspension related problem?

Even more weirdly, the car has been back to perfect with no vibration at various speeds in the past 2 days. But, I didnt go into boost since the shaking to avoid any damage to the turbo or engine.

My noisy front anti-roll bar drop links are still not replaced. And, I am really worried Could the sticky weight used in the inner wheel for the balancing job be loosened by the heat during the spirited run? All I did was 3 launches from lights to stop.

Would anyone please help to diagnose this problem?

[Loren]

I doubt the weight was loosened - more likely you moved the tire on the wheel rim with the drag strip starts. Lots of torque there.

The real test would be to take a tire or two off and see if they are still balanced. You could also make a mark (crayon) on the wheel and tire and see if they move.

Most problems like you are describing are tire related.

[niceguy]

Thank you very much for your insightful and experienced answer, Loren!!!

I will make the marking on the tire and rim tonight. But what if I dont plan to do any more launches for a while? Is getting the wheels balanced again the only cure to this tire-related strange vibration?

James