Ok - here is the news
 

I did find (surprisingly) several dealer with the Hunter GSP9700 road force balancer. These guys make a killing business here - I guess, the have a patent on that.

Anyways. to make a long story short. I have one wheel in the front, that is completely out of whack. It is vertically unbalanced and uneven - not sure how to call that in English. The outside of the wheel runs ok, but the inside bounces at leas 2-3mm. That of course is worse at 40psi than at 20 psi. The machine likes 40psi to take better measurements. We tried it with wheel only option and wheel an tyre - and the hunter machine threw a big red screen "ALERT ALERT".

We turned the tire about 4 times (each 90 degrees) on the wheel - but with an unbalanced wheel, the effort was hopeless.

How is this possible ? Looks like a brandnew Halibrand knock-off 15inch wheel.

We did what we could and added almost 4 ounces of weights (inside an outside) to bring it to 0 during normal balancing (without the big roll that simulates the road force action).

But the wheels back, brought down the pressure to 21psi and turned the suspension (QA1) down to 4 clicks from loose.

The steering wobble is almost gone. I can still feel it a bit at around 70mph. However, I did not fix the issue but just covered it up with soft setups.

So - road force balancing is a good thing. Helps to see issues that a normal wheel balancer couldnt.

Now, I need a new wheel. I hope, I can still find a wheel with the same color as they made it in 98 . Do you have any ideas where to look for one ?

Thanks guys

Jürgen

This might be an optical illusion - the bright red rubber is the part that was covered up from the washer and the darker one was exposed to the outside. I do believe it is the standard setup.

And yes - I did already touch the A-Arm. Pretty scary stuff, I have to admit, especially since I was on the Autobahn with it bouncing and clonking all over the road ... boy of boy

Laters

Jürgen

Tommy, you are right. It is not rocket science and I've been around cars and bikes all my life. My SPF was driven by a very careful gentleman. It still had the original tires from 98 on it when I bought it last year.

I'll get this baby straight and right. The input and available information here in the forum is amazing. Perhaps, I have to invest in a few suspension upgrades - but hey .... the last shirt has no pockets.

Laters

Jürgen

You mentioned earlier that you have car #1385. If it was from 98 and had avo shocks is it # 385?. 1385 would ha e been made around 2003 and have bilstien shocks from the factory. My front end shake turns out to be the drive pins were slightly too long for the after market PSE wheels causing the wheel to not mate up to the hub.

sorry - get confused sometimes with the frame-number and the actual number of production.

My car ist #385 like you mentioned correctly - from 98 in guardsman blue.

Good point - could this have "warped" the wheel and what did you do to it. New pins or shave them off?

Thanks

Later

Jürgen

I shaved the pins.

I had the shimmy problem and found the front tire to be out of round just by jacking up the front end and manually spinning the tire while it was off the ground in my garage. One front tire was visually nice and round. The other tire was noticeably out of round. Replaced the tire (I got a sizable credit from Michelin) and the shimmy went away!

Followed this thread. Glad you listened to the smart ones about the gsp9700. Sounds like you found some knowledgeable people. Log who they are on this forum and stick to the shops with the right eguipment.

Just wanted to follow up on my root cause research of my vibration issues.

We did the road force balancing and noticed that one wheel was way out of balance. Luckily, I found a new wheel from Trigo (thanks for the quick and friendly service) and the vibrations are almost gone. The Avon tires don't seem to be the "roundest" tires out there - the diff in necessary balancing weights with and without tires is 80 gramms and it makes a hugh difference when turning the tires on the wheel in 90 degrees steps.

Now - I do have a "shimmy" movement (not near as intense) from the front end at around 70-85mph. I've been reading up on the R/T ball joints and will probably go that route, hoping to be in the right direction.

Thanks

Jürgen

I'm glad its getting better. ... I stumbled on this pretty good short video about fixing a shimmy problem. [ame="https://www.youtube.com/watch?v=lLqF7A3SAXE"]Click here[/ame].

According to Cobra Valley, factory ball joints cause a wobble at 65mph even with perfect tires.
He sells replacement ball joints for this exact problem.
Call and talk to him for first hand info.
Dan