New Tires - Run Flat Break-in - Sterring Wheel Shake

[Anthony Cundari]

Has anyone had this problem: steering wheel shake after new tires installed. Then it disappeared after 1000 miles!

Tires: Goodyear Eagle rs-a. Emt. P235/50zr18
The Cadillac dealership uses a Hunter GSP9700.

Technician noted that 3 of the 4 wheels were bent and hilited the service record on this if the customer noticed vibration.

Leaving the dealership and not seeing the notation on the bent wheels I headed home and got up to 70 on the bypass. Instead of a nice smooth ride the steering wheel started shaking (cw/ccw/cw rotation of about 3-5 degrees). Went away when I got down to 50 off the bypass. A couple of days later after it had sat in the parking lot all day, I experienced severe shake for the next 15 miles of my ride home at low through cruising speed. After 250 miles I brought it back to the dealership. They rechecked all 4 wheels and tires and said everything was within spec except for the Hunter still indicating 3 bent wheels.

Took a business trip to MIchigan 2 weeks ago and noticed that the shake seemed to come and go. Different road surfaces, different lanes, 2 hours + of experimenting.

Yesterday I drove to work on the bypass and no steering wheel shake! Same thing after work! Same thing this morning. Now after 1000 miles, the shake has disappeared! Tire pressure has been and is at 30 psi. Spoke to the Service Manager this morning who has personally been involved and has driven the car and he is scratching his head. His only thought is that the EMT 's are much stiffer when new and now they are becoming more pliable with use.

Does anyone have a good explanation?

One other note: the dealership matched the internet price + shipping for the tires.

2/12/12 Update: the Dealership tracked down a Goodyear engineer who was familiar with the problem. He said the new run-flat tires are more stiff than tires with 18,000 miles which is what the car had when I bought it. Combination of bent wheels and new stiff tires will cause the vibration effect that I was experiencing. Also stated that the change in vibration, vibration coming and going, that I was experiencing could possibly be due to 2 wheels moving in or out-of phase with each other magnifying or cancelling the vibration effect. I watched one of the bent wheels on the Hunter and I could see the follower dip when it hit the depression in the wheel as it rotated. Bought 3 refurbished wheels (1 original wheel was OK). All the vibration is gone. Foster Chevrolet Cadillac has been EXCELLENT in working with me on this.