i'm getting a pretty bad vibration at 70 mph on a smooth interstate and its a little unstable...i've balanced the tires, rotated the tires, checked the rims for trueness and if they were bent or not and the front end is tight, i have studded cooper weathermasters with only about 10,000 miles on them and they are not choppy...i'm wondering if anyone has had a vibration from studded tires or maybe i got a bad batch of tires...tires are set to 30 psi which is what is recommended...should i try and roadforce match balance them (we got the machine where i work)....thanks in advance for any input

How are your rotors?

they look new...i just bought the car...and the vibration is while im driving with cruise control set...it brakes smooth...no pulsation

They don't have to be warped to cause a vibration. They can just be off balance and cause a vibration.

Have you tried rotating the front tires to the back to see if you still have a virbation?

It could even be one of several different suspension parts. My ball joints caused a fair amount of vibration above 70 mph. It wouldn't hurt to check other parts of the suspension.

I am however not familiar with studded tires and don't know if that could be an issue.

i have rotated the tires front to back and i've checked the front end and its tight, maybe its the tires...when spring roles around (12-18in snow coming so i'm not switiching now) i'm gonna throw my goodyear eagles back on and see if it goes away...unless i can find something else in the mean time...i just remembered, i had the same vibration in my 94 sse but the turned out to be a badly bent RF wheel (Same snow tires) would the rotors cause a vibration without applying the brake...maybe i should turn them at work

How does your harmonic balancer look? Make sure the rubber hasn't started to seperate from the metal.

You shouldn't have any vibration with a bad harmonic balancer. Mine was destroyed, yet it drove perfectly normal. Idling was smooth as well. The only symptom was the clattering noise.

The only time I could think of someone having a noticeable vibration from a harmonic balancer would be if you had the wrong one installed on the car.

If I read that correctly, these are the same tires that were on the bent rim. If it was run that way a while, it'* possible you have a strange wear pattern on that tire, and that is what is causing the vibration.

This was not the case with my L36. I replaced my failing hb and vibrations on the highway went away.