So, I've had a pretty bad 55-65mph shake going on with my car the last few months. Now that I'm driving 50 miles a day at highway speeds I wanted to get it fixed. It's been 75k miles since I last did the control arms, tie rods and front shocks, so I thought it would be the problem. Took it to my trusted mechanic, and he says there is nothing wrong with any of the front end components! Suggests that I get the tires balanced 'on the car'. (I just recently had them balanced with a Hunter Road Force balancer - it made no improvement.) The tires are about 1.5 years old and still look good, but maybe there is a bad one? Flex disc is also okay.

I can feel the shake in the steering wheel and the seats, pretty much the whole car shakes. It doesn't shake all the time though- sometimes it seems to take a while to start up - maybe the tires need to warm up?

Anyone had something like this? Any advice?