swap front and back tires worse case. if they fit. go drive in straight line go test. pull over and switch em back. k did this once to prove go myself it was a wheel issue. vibration went from steering wheel to seat. ,,, proven

I would jack up the front and spin the tires by hand. Carefully watch the tread for trueness when it spins. Spin balancers (don't get me started on those) won't fix an out of round tire. It happens more often than you would think.

Thanks guys,

Lots of great info, it looks like I have a few things to check.

The rubber is fairly new, about 2 years 10k miles. The wheels are the same so I should be able to swap and see what happens.

I will update as soon as I have somthing to report...

Thanks again for the info.

RBL>

Gordon made a good suggestion. I've seen quite a few egg shaped tired over the years. The speed the shaking occurs depends on the shape of the tire and the harmonics with the road it develops at different speeds. But that's only one possibility to go along with the others.

Though everything mentioned in this thread is a "possibility", imo the "probablility" is that it's simply poor tire balancing. I take my mint condition Fuchs off the car and take 'em to the local tire shop where I insist on watching. Last time, the "kid" balanced three of them (taking great care) with no problem, but the last one still wasn't balanced after three attempts. The manager came out and took over.....took him several attempts, but he finally got it right. If I hadn't been standing there watching, I GUARANTEE that I would have been given back a tire that wasn't correct....YMMV.

So glad you got it sorted out cheap. Happy again:)

Find a shop with the old on car balancing equipment. It's a given that the adapters sometimes won't fit modern wheels but it will allow the technician to get the wheels up to the vibration range and eliminate front end components and wheel bearings. Spinning the front wheels (rotors included) on the car will narrow down the search. For the rear you can jack up one side (or jack the rear end and one wheel) remove the opposite tire and have a buddy start the car and spin the wheels to the speed where the vibration is the worst. This method can be broken down to the various drive axles and rear brake rotors too. I've had a few cars where in the front, the tires required a "road force Balancing" done by a tire dealer. Some times tyres will check out OK by static and dynamic balancing but once the road force prevails, they vibrate. A good road force balancing machine can shave the tread carcass of moderately vibrating tires to correct them. Another trick for questionable brake rotor balance is to install the brake rotor on the wheel balancer along with the wheel / tyre assembly. This will require the assemblies to be "indexed" in relation with each other and installed back on the car the same orientation.