I bought Pirelli P-zero neros in a 225/40/18 from tire rack for my 07 SS/SC. At first when I got them mounted in New York I drove to Ottawa and realize the asshat didn't balance them well, so I had them balanced again and then continued on my way.

Well progressively since the second balancing, there is a vibration that starts around 60 and gets worse with speed. I used to take her all the way up to 146 with no issues. Now at 70 I can notice it. But here's the thing. I took the wheels myself to the Auto Care center on Hunter Army Airfield, and I personally balanced them myself.

When I was balancing them, I notice 2 tires were balanced perfectly, but looked like they were out of round. Like the tire wasn't perfectly circular. Could this happen to a tire? Anybody got any ideas? You would think pirelli p-zero neros wouldn't do this for 190 a tire...I've been looking at Kumho Escta MX or something like that for an alternative if the tires are just defunct.

Or does anybody thing a worn suspension component would cause the tire to become out of round with time? The car is at 37,000 and has never had an alignment...

 

hmm i'd say tell tire rack sounds like the belts in the tire

 

New tires come 'out of round' straight from the factory all the time. Sometimes it's just the way they were mounted (ie: not enough lube). A trick tire guys like myself do is to remount it with more lube and turn the tire 180 degrees on the wheel from where it was mounted before.......if that doesn't work, then the tire should be replaced (if it's that bad).