Ideas - what could be causing a steering wheel shimmy?

[burbel]

Hey all, I tried a search but didn't find anything covering this.

This last weekend I spent some time trying to raise the rear height on the Tein RA's to cut down on negative camber to try and save tires.

I also lowered the front a small amount, the rim -> fender gap went from roughly 12cm to 11cm, not a large change.

I remounted the front tires and took it for a spin around the block. The car has now developed a pronounced steering wheel shimmy at slow speeds (never got over 20mph).

I was planning on getting an alignment; does this sound like it could be alignment-related, or does this mean that either I broke something or didn't put a wheel back on properly? I'd like to get this figured out and fixed if it's not an alignment issue ASAP, before I go to the Hunter machine.

 

[nsxtasy]

A vibration or shimmy can have a variety of causes. The most common cause is a tire that's out of balance. If you happen to have an extra set of wheels and tires that is known to be balanced (or can get together with another local owner who has one), swap the other set onto your car and see if the vibration disappears. If it does, then it's definitely the wheel/tire balance. If not, then you should start looking at your front end, including alignment, worn bushings, etc.

 

[KGP]

I remounted the front tires and took it for a spin around the block. ...
I...didn't put a wheel back on properly?

Just for shits and grins, check your lug nuts one more time.

 

[D'Ecosse]

I assume this wasn't there before & just appeared after your adjustments - possibly something worng with your wheel mounting - are your hub-centric adapters positioned correctly? Perhaps your wheel isn't on "true"

 

[nsxtasy]

Just for shits and grins, check your lug nuts one more time.

Come to think of it, even when a wheel is out of balance, it doesn't usually show up at speeds that slow. So I think this is a VERY good idea, that it's possible a wheel wasn't on tight (as both Gene and Ken have suggested).

Rather than just checking that they're on tight, I would loosen and re-torque all the lug nuts (jacking the car in the air in the process).

 

[burbel]

Thanks for all the hints; I will definitely bring the car up and re-do the rims/lugs. I checked, all the lugs are still holding at 80 ft.lbs. When I seat the rim using the lugs I tend to "wiggle" it back and forth until the lug seems to bottom out; maybe I didn't do that on one side this time. I hope it's nothing serious.

 

[burbel]

Well, this was unexpected. So I checked the lug nuts on the driver's side (they all seem centered), removed the wheel, remounted after rotating 180 degrees, and the shimmy was still there.

I removed the passender side wheel, and once I pulled it off the lugs I heard something metallic falling. Turns out it was the retaining spring for the hub-centric adapter in the SSRs. I had brought this wheel in to get a puncture plugged; looking at the scratches, I guess while it was in there they tried to get the hub-centric adapter out, and, if I had to guess, bent the spring while they were at it.

Got it back together and it's doing good now; I'm going to contact the tire rack and see what I can do to fix this going forward.

Thanks all for the help/advice!