Mr.Pink,
I've chased the same problem for two years. I've changed much if not all suspension parts. I've had three sets of tires on the car, two sets of BFGs and lastly a set of Yokos. I've had the tires/wheels dynamically balanced, statically balanced and road force balanced on a Hunter at Moroso's speed shop. None of which cured the problem. I've had anywhere from 15-25 ounces of weights on my wheels and every time they seem like they get put in different locations. I've had the weights installed on the inside and outside of the rim. I've had the wheels trued round within .001" then reinstalled the tires, balanced again and STILL no luck. I've checked the wheels ON the car to confirm that the rotors/wheels are true.
I put my car on jack stands and put it in gear and let it idle while I checked the OD of the tire. My
vibration in fact came from the tires. You can see the videos
here and
here
The ONLY thing that I've found that cured my problem was having the tires shaved. Bob in CT found a place that will shave the tires even if they've been on the road. I only had the fronts done and 90% of the
vibration is gone. I went from needing 20 ounces on one tire to needing only 1 ounce. I was so happy that I never took the time to take the rears to have done as I've been enjoying the car much more. I'll take them to have them done this winter.
Some tires may be better than others but most fat 15" inchers have the potential to cause problems as our cars are so light. A dampener will help but your masking the problem. My thinking was that if F1 cars can get by without a
vibration, why shouldn't mine? They run a solid link
steering as well so why don't they have a problem? Yes, our cars feel every little bump and given the same tire on a 3500 pound car, you probably wouldn't even notice it. Any amount of bump-steer will amplify the problem so make certain you've got that under control as well.
My $.02 worth
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