I have been driving my 2007 GT with the stock 17's on the car and I recently put some new rims on 18x9 Front and 18x10 on back (Thanks to my wife for the big 40th b-day gift. In 10 more years I can buy the suspension). I noticed that at about 50 to 60 the steering wheel would shimmy alot. I had a wheel alignment done and all four wheels rebalanced. They found the alignment off a little and the front wheels needed to be balanced and more weight added. American Muscle stood by there free mounting\balancing of tires and credited me for the re-balance of the front tires. Now at about 60 to 70 there is a slight shimmy in the steering wheel, almost a little visually noticable vibration. Is that normal? If not, what else should I check?

thanks for the help,

Gary

 

A shimmy can be anything from a miss-balanced wheel, to a wheel that wasn't mounted properly.

Try taking the wheels off first and remounting them. Make sure you use the standard cross-star pattern for tightening the wheels. I normally use a breaking bar and put all my weight on the lugs, but I believe the spec is for 80 ft. lbs of torque per lug.

Drive it again and see if that shimmy is there. If it remains, it's likely the wheels are still out of balance.

The problem with most balancing is that it's done with zero load on the wheel. It doesn't accurately simulate what's going on with the wheel/tire package when it's on the car. This is why road-force balancing is such a good idea.

There's also a difference in where the weight's are applied. If the wheel is out in the center but the weights are applied to the rim, it can't adequately correct the balance of the wheel.

Another possibility is that one, or both of the wheels on the front of the car aren't perfectly round, or have too much run-out. We all like our replica wheels and most the time it's not a problem. However, they are cheap wheels and sometimes this type of thing happens. It's why you end up paying thousands of dollars for quality wheels.

 

I had the same issue after my 18x9.5 CS69s were mounted and it ended up being a balance issue with the fronts. After the second balancing job, the shimmy was gone.

What type of balancing machine was used as a RoadForce will defnitely help ensure it is right on... especially with wider rims.

 

Ditto, call around and find a shop with a Hunter RoadForce machine...

 

Did you take off the lock washers on the front studs? There's one on each side. That might help slightly. Helped with mine. I have some shimmy in mine at times too. But I need to get the alignment checked cause I went down a dirt road and might have knocked it out a little bit.

 

+3 on the Hunter Road Force Balancing. I had a set of 19" Saleen PJ rims on my 07GT. The steering wheel had a slight vibration from 45-70 M.P.H. My Ford dealer balanced the rims twice with no luck.
I went to the Hunter website, used their dealer locator to find a nearby shop with the road force machine.
Had the wheels road force balanced and the vibration was totally gone. Here is a link to the Hunter dealer locator.

http://www.gsp9700.com/pub/search/findgsp9700.cfm

 

Thanks for the information. I will look into that Hunter Road Force Balancing.

-Gary

 

Before you do anything, pull off all your wheels and check the lugs for small retaining rings. The factory is bad with leaving them on and they will definitely cause the issue you are describing. They are used during assembly to keep the rotors on. I'm willing to bet you've got one or two on there, especially since you've already paid or balancing and an alignment.

 

Ditto what TGREY V6 and DarkFireGT said, check for the rotor retaining clips first. The factory wheels have a chamfer on the back side that allows clearence around the wheel studs to let the wheel seat properly even with those clips still on. Most aftermarket wheels don't have the chamfers and won't sit flush without the clips pulled off.

If that isn't the issue, then Hunter RoadForce balancing is the next step.

 

Also torque those puppies to 100 ft lbs. After a 100 miles or so check the torque again. G/L

 

Yes, retaining clips. Those are the words I was lookin for. That helped a lot when I took mine off.

 

you can also try to narrow it down by putting one of your rear tires on the front and the front tire on the rear and see if that improves any, if not try the other side.

 

+1, this is VERY important! New wheels will seat/settle and a re-torque will be necassary for saftey. Back in my younger days I worked for a tire/wheel shop and we had several 3-wheeled cars come back in over the years after they failed to return for a wheel re-torque on new wheels. Not real common but batter safe then sorry!

Tim

 

This is what it looks like..





Also what Rich said, if you don't have one, buy a torque wrench and torque the lugs in a cross pattern to 100 ft lbs.

 

I have some time on Tuesday. So I will be removing them and checking for the retaining clip.

Thanks,

Gary

 

Yup, those darn clips can get you every time. Got me when I put my 18s on a few years back.

 

^Ditto when I switched from stock 17' to 18" Deep Dish..

 

**** it I had no idea why mine had that shimmy. Glad I read through posts! Now I'm going to have to check mine.

 

I took off one retaining clip off 3 of the bolts and 2 off of the other one. I have driven about 100 miles at various speeds and the shimmy is now gone. Not sure how someone figured this out, but I am glad they did.

Thanks for the help.

Gary

 

Those Clips are called Tinnerman Clips as an FYI. No Need to remove if you run OE wheels with the Back Cuts on the Inside. A Must to remove on a wheel with a Totally Flat surface or spacers.

KC