Greetings! This is my issue:

Have a 2004 MCS for about 8 months now. I changed the wheels and tires around 2 months ago, before changing it I did not experience any issues with vibrations or the sort. After adding the wheels and tires I get a really bad vibration at around 40-60mph. This vibration is non-existant at lower speeds. I also have lots of torque steer. When I get on the gas hard, the car is all over the place. Once I had to literally turn the steering half a rotation to the left to keep it in a straight line. I'm not sure why this is happening since I made it a point to replace the wheels and tires with the factory specifications : 17 inch wheels, and 205/45 tires. However, I did need to use hub rings and suspect this might somehow be causing it? . I'm really not sure what to do next. I've had all wheels rotated, balanced and had the car aligned and still no change with the vibration :(. The vibration is not just something I feel in the steering, if I leave the wheel doing around 40mph, you can physically see it turn really really quickly from left to right, very small quick movements, but the car still goes in a straight line, the steering just wobbles! :( help?!

Also, I'm not sure if this is related, but when I reverse, I get a loud "Krack!" Noise from the front wheels. (Not sure if its one or both) Almost as if they're loose or something down under there is missing a few bolts!

 

Need details-what kind of wheels and tires did you take off and why. What kind of wheels and tires did you put on. That would be make and model for those. Were the replacement wheels new or used? same question for the tires. Anything else you can think of.

If the wheels were supposed to have center rings, then absolutely they must be in place otherwise the wheels won't be centered and you could overload the wheel bolts.

 

Sorry I failed to mention that. I took off the 17" S-lites and Continental 205/45 Run flat tires. Reason : Tires needed to be replaced, were in really bad condition, and the wheels were scratched at the edges so I decided to take them off and box them in my garage. I now have 205/45 Pirelli NON-runflats and 17" BBS Wheels (both brand new) . I've also checked the wheels for any damage or dents, but they're perfect. I think its those center rings!

 

Brand new tires have been known to be missmouted or miss balanced...also new rims have neen known to throw weights...or have been bent in shipping.
Since you know the change happened when the rims/tires were swapped, i would start there.
The thunk/tourqe steer could be related to a cv joint ....but that should become rapidly apparent. Since rims/tires will usually be warrentied from the seller....so having them reballanced should be free...so easy 1st step. Hubcenrtic rings are sold in several sizes....just make sure they fut both the rim perfectly and the hub on the car...one size hubcentric rings is only. 5mm off from the mini..but having a wheel mounted that far off center could give you a shake...
Bad tire from the factory could do the same....
Brakes feel ok...no pulsation when hot?

 

Just an Update:
I do actually get a pulsation from the brakes when they are hot, this has only happened twice. ive also decided that im going to put the stock wheels back on and run with it for a while to see if it cures the problem. if not, i can add it to the growing list of things NOT causing my steering wheel to shimmy. so far ive
- Balanced and Rotated all tires
- Checked for any damage or dents to the wheels
- Aligned the car
and now im going to remove all wheels and hope that the shimmy goes away :( . could a mushroomed strut be causing it?
if the steering still shimmys and vibrates, then i guess that there is some problem with the car and not the wheels.

 

I think going back to the stock wheels and tires is a good idea. That should be a good check.

Let us know how that works out. When you change the wheels, check the hub centric rings on the new wheels for any looseness to the hubs. Also note that shocks don't cause vibration or cure it. They will dampen a vibration, but vibration is caused by something moving, generally it will be something rotating.

 

I had a bad tie rod end that caused a shimmy between 55&70

 

brake pulsation when hot points to warped rotors...it will gradually worsen....
shake in car/pulsation in pedal, but not in steering often means the rears are warped...pulsation in pedal and a steering wheel shake often means the front...
other things like bent rims, bad tires, etc can do it too, but it is something to look at. Checking rotors for warp is pretty easy...and YOU DO HAVE A PULSATION....so my bet is you found your issue...
And a mushroomed strut tower throws off your alignment...so yes...that could be an issue.

 

Ok, so much for generalities. However with a vibration, I would look at rotating parts first, then loose parts.

 

The first set of aftermarket wheels and non-run flat tires that I put on my '04 (way back when) gave me the same results. Someone suggested getting the tires road force balanced instead of just balanced. I Had them road force balanced and the problems disappeared. I don't know the difference between road force and just balancing but have had all my wheels/ tires since then road force balanced and never any issues.

 

PROBLEM SOLVED!
I was in the process of removing the aftermarket wheels to replace it with the Stock 17" 8 spoke wheels. I noticed the hubcentric rings had some play to them. They actually could spin on the hubs. This diddnt look right to me, so I went and got thicker hub rings . It was a perfect fit. No spinning or play to them. So I figured I'd put the aftermarket wheels back on to test if the hubs were causing it. And joy of joys, no vibration! Drove smoothly! Still can't believe the hub rings were causing it! - next fix, my mushroomed struts!

 

Fantastic

And thanks for following up with what you found.

As for your mushroomed strut tower...here is a little different route that will get you much better handling and a stronger tower:

Get a set of IE fixed camber plates (Ireland Engineering). These are made with a 1/4" thick steel plate and a much stronger strut bearing (from a Z3, I think). These fit on the underside of the strut tower where the added strength is really needed. They will also move the strut inboard to give you about -1.6 deg of camber. A great improvement in handling without tire wear. You will need to pull the struts to put them in. Not a hard job if everything is not rusty.

 

What about those of is with stock wheel? I've had everything balanced and rotated. Wouldn't a shop notice a bent rim while balancing? Did the wheel bearing test, lca bushings were replaced with powerflex, suspension links don't have abnormal movement.