[Bob In Ct]

Hey Jim:
Believe me I read your link. I've put a lot of thought and effort into trying to eliminate this problem. While I understand that it may go away for some owners when they balance the tires or get the wheels aligned, for some of us it just goes on.

I would love to put my tires on one of these Hunter machines your link recommended but I have not been able to find one. I am convinced that 90% the vibration comes from the tires with maybe 10% coming from the wheels. I understand that tires that are dimensionally round may not be round dynamically. When they roll under load they go up and down. When I worked for Armstrong Rubber (as a tire engineer for 12 years) we had a machine that could identify these out of (dynamically) round tires and correct them. It was only used for OE tires!

There is a good chance that little cars with big (heavy) tires are more prone to this condition than are heavy cars with little tires. One the harmonic sets up (60 to 80MPH) there is really no way to stop it. I think the shake comes and goes because the tires do not roll at the same rate and cancel and reinforce the vibration as the car progresses down the road.

I have been driving now for 40 years. When I started driving in 1962 there were no such thing as dynamic balancing or computerize alignment. In spite of lacking the new high tech gizmos cars of 40 years ago did not have steering wheel shake! I driven a number of rust buckets over the years and none of them had steering wheel shake!

Could it be that radial tires and Cobras do not get along well? Could it be that Trigo wheels are not round?

Bob