03 Park Ave Ultra vibration

[J J]

I have an 03 Park Ave Ultra with 17" tires. I developed a shimmy so took it to the Buick dealer. I had Cooper cs4 tires that were GREAT! They told me those tires could no longer be road forced balanced with 20K miles on them, so I put the original Eagle tires back on. Same exact problem. Dealer said you need new tires so I let them try. 6 sets of tires later and hundreds of $$$ in road force balancing later, they say they got it as close as they can by putting different sets of tires on the front than the back. All suspension has been checked and found to be good. It was perfect with the Coopers til I developed a slow leak in one tire, so they fixed the leak and it has had a vibration ever since. It is my understanding that if a rim was out by even a little, road force balancing would pick it up. I am ready to dump this car! It only has 78K miles on it!!! Am I going to have to go through this every time I rotate the tires ? I had the dealer put my old tires back on, and now I need to decide what to do next. ANY suggestions beyond the obvious would help, as I am at my wits end with this vehicle - which BTW is mt 4th Park Ave. I would NEVER get an Ultra again!

[xs03mich]

I had a same type of problem, though it was with a new set of tires. Road force would not get it right. Found a garage that works on frames and large trucks. They balance the tires right on the car, shimmy is gone. The bad news it was 125.00 and it will have to be done each time I rotate the tires. On the upside the ride is superb. Good luck, as it can be aggravating.