rpcollett. Is it a shake or a vibration. two different animals. Bad rack would not cause a vibration. It would certianly be more pronounced with a bad rack. due to the rack not holding pressure.

 

yea id say its definatly a shaking, cause if i have drinks in the cup holder they go nuts and shake all over.

 

start with re balancing the tires.

 

I'd suggest rebalance first also. I have a set of MT's that shake dramatically at 45mph, then no more after that. Just had them rebalanced again with new wheels.
shake is still there, just want to wear them out then new tires. If you can get them road force balanced, you may find an additional balance point necessary to stop the shakes.

 

Kinda sounds like death wobble, could you get death wobble with a ifs?