Front Wheel Shimmy

[GeorgeM]

I purchased a set of Goodyear F1 GSD3s about 18 months ago. It took an excessive amount of weight to balance the fronts, but they balanced. After about 9 months, they began to shimmy and I have since been unable to balance that shimmy out. I've been to four different shops to have them done, and although they balance on the machine, they took lots of weight. I've had no such issues with previous tires on these stock Fuchs rims.

The Porsche dealer suggested that they might be defective and out of round. So I had them replaced for free under warranty/road hazard contract ($40 well spent).

I had the new ones mounted and balanced at the Porsche dealer yesterday. I was all excited that these new ones took a normal amount of weight to balance. But, I drove the car this morning and they still shimmy at about 80-90mph.

I'm not sure what else to do. It's obvous that the previous tires were defective. These appear to be okay. Did I perhaps ruin my ball joints or something living with the shimmy for 9 months (although I only put about 5K miles total on the defective tires)? I'm sure they are the original ball joints with 133K on them. The turbo tie rods are only 20K miles old and all bushings were also replaced at that mileage with Weltmeister poly.

What do you guys think? I'm very frustrated with the situation and the car sits in the garage a lot because of it. I have some great drives coming up to Ruf, Gmünd and Nürburgring and only 5 months left of my tour in Germany, so I need to figure this out.

Thanks.

[b. hilliard]

I developed a shimmy in my recently re-balanced Yokos, but quickly traced it to a front caliper dragging on the disc. Rebuilt calipers and shimmy dissappeared..... The steering is VERY sensitive to any outside input, obviously.
Good luck.

[BReyes]

Check the ball joints, and all usp comp while you are there. It sounds like it is the tires. But it doesn't seem serious enough. New ball joint(s) would be nice next service.

Good luck.

Regards,

[Keith Perry]

B. Hilliard is spot on, for me anyway. I just put new Yoko's on the front because I tore a hole in the old front right and had to patch it on the inside to get home, shimmied, didn't like what was going to be excessive weights to make it better, lived with the shimmy for a month or two (stupid me) and still having a slight shimmywith the new tire above 70mph, read his post went outside and pulled the wheel off to find that the outside pad is dragging and has worn more in a month than in the previous six months. so, it's time to rebuild the calipers. I did the hoses not too long ago. The inside of the front right was swollen shut.

[Carl83911]

When does the shimmy occur. Is it speed specific? I began to notice a slight shimmy in mine at around 75mph then goes away once past that speed.

[GeorgeM]

Thanks for the inputs so far guys.

I had them rebalanced this morning and had the guy put the outside weights on the outer lip instead of inside the spokes. It's better than it was, but still a slight shimmy.

It usually seems to start around 65-70 mph. It dampens out slightly above about 90. Haven't had a chance to get it above 100. It's inconsistent though; sometimes it won't start 'til 80mph.

The ball joints look fine, no play. The bearings look okay. The rotors are in great shape and spin freely with no brake drag. It was suggested that maybe the strut inserts are worn, but they only have 20K miles on them. Although, I did have to replace my rear Konis prematurely because they started leaking.

I ordered all the ball joint parts anyway, so we'll see if that does anything.