Wow, this makes your head spin, especially since I need new tires and am looking at Conti, Nitto or Goodyear F1's.

 

You may have a point there. Last week a trouble shooter from Sullivan Tire in Boston came to the place where I bought my tires again. The last time here looked at my tires he ended up replacing the 2 front ones with 2 new ones. That improved the vibration a lot but there was still some there. This time I left the car there all day and when he called me to say he was done he told me he checked everything both suspension wise, tight calipers and the tires. He found nothing wrong mechanically with my car. My car has only 37,000 miles on it. He did however find a little out of roundness with one of the front tires. He replaced the tire with a new tire. He drove the car and said the vibration was gone however at about 54 mph he said there is a little. I drove the car and couldn't feel anymore vibration. There is however once in a while a little vibration at 54 mph but like I said. It doesn't do it all the time.

So now after replacing 3 of the original new tires I bought and after several hours at the garage I now have only a slight vibration but it is only intermitent. I do like the way my car rides with these tires much better than with the Yokohamas I had. But your point of there being something that has worn that would cause the vibration is well taken. Before I put my car away for the winter I am taking it in to my Chevy dealer and I am going to ask them what they think. If you ever find anything out about this issue please let me know.

Thanks

Bob

 

Last year I checked the half shart u-joints and 3 out of 4 were bad.I replaced all 4 .This car only had 70k miles on it but being 18 years old I suppose the grease drys up.Ofcourse this didn't fix the problem.At times it will run smooth at 55 and awhile later it will vibrate.I wonder if it has to do with how the road is paved?Also I wonder why chevy went with different width rims on c-4's?8.5 on the front and 9.5 on the rears.What was there reasoning?My 84 had16" x 9.5 all around and I don't remember any vibrations on it.Also my 2000 is very smooth.It too has different size wheels front and back.It would be nice to hear from someone that has solved this problem.BTW: I did have the tires road force balanced and no different!