Vibration (also posted in the drive train section)

[nicktowe]

Hope someone can help

I have a vibration (lucky me) that gets worse with speed. It is imperceptible until doing 90 + leptons and gets worse as i go up to 120 etc. The frequency increases with speed and is not gear dependant. All wheels have been balanced, and propshaft uj's greased etc.

What are the liklely causes? I am off to some european circuits for tracvkdays, so could do with getting it sorted.

Thanks

Nick