Edward

Hi all,

Any of you guys get a slight wheel shimmy (sterering wheel occilates about a good 1/2") at about 50mph that then *disappears* when going faster (or slower)? I don't get it. The wheel is rock steady at speeds well above 50. If it were truly a wheel balance issue, would it not get progressively worse with increased speed? BTW, the tires have <3K miles and look excellent. Thanks!

Edward

Alon

Check the following (in this order):
1- tire pressure for front tires, (also check condition of tires. Look for uneven wear patterns along the outside edges)
2- check torque for front wheels (you might as well check all). They should be tightened to 96 pounds
3- are you running any front spacers? If yes, are they hub-centric. If not, go to next step
4- check wheel balance. A vibration/shimmy that is speed sensitive but smooth at high speeds is not uncommon
5- check alignment - incorrect toe settings can cause this
6- check tie rod ends, steering rack, etc.

Report results back to us.

kdurg

Hi Edward,

Yep, I've been battling this problem since I've owned the car and have researched it to death. I've had several road force balances and alignments to cure it...no luck . I've replaced tires, rims, steering rack.....it still won't go away. The shimmy is very slight in the harmonic range of 55-60mph....other than that, the car is spot on.

I've noticed the shimmy is more pronounced when brake dust buildup is severe and less pronounced when the rotors are cleaned out.

I've also seen posts where new rotors come with balancing pins in them ???? Not sure if this is the culprit but at this point I've chalked it up to the car's personality and consider it additional "road feel'.

I haven't been able to dial it out with any type of regularity.....so if you come up with a solution, please let me know.

TroyN

I have had this, but only when first driving the car after it's sat for a week or more, and when I was running 32 psi cold in the front. In my case the tire was flat-spotting temporarily from sitting, but I now run 32.5-33 psi and it doesn't do that anymore. It would go away once the tire warmed up and I had driven the flat spot out, so not sure if that's the same as your car's behavior.

Davies

I have the same problem, and like TroyN, it goes away once everything is warmed up.
I know that powerwashing the brake dust buildup out of the rotors can sometimes help.
A lot of crud settles in there over time and can cause a slight judder in the steering wheel.

Edward

Thanks for the feedbback, all!

What I do know is tire pressure and tire condition is good, lugnut torque is right, and alignment is correct. Nothing else "appears" worn, loose, or otherwise bad as I have checked underneath a few times. Mine is a daily driver in warm SoCal so I doubt it's anything like winter flatspotting, but I wonder if it happens on my way home from work when it's way warmer ...it's a thought anyway so I'll pay closer attention. Didn't think of blowing ou the rotors, though. I used to do that regularly when I tracked it and changed pads but now no longer. I'll check that out, too. Thanks a bunch, guys! Take care!


Edward

Evan

Edward,

I had it as well right around 55 and then again at 80 (not as bad). Alignment checked twice and front wheels checked for balance. All was fine. My front tires were (still are) wearing on the insides (almost to the cords) and the outside tread is like new. I had them switched so I have the good tread on the insides now and the shimmy went away. Solid all the way through 80.

The tech thinks it maybe worn inner tie rod ends. That is the next item we'll check and see if it that is the cause of more than wanted negitive camber.

Terry Adams

For me, the front shimmy happens every time at 58 mph when the wheels are not balanced properly. And goes away at higher speeds.
If you have done everything suggested above, especially Alon's well ordered list, what is left is
1. Find a shop with a Hunter GSP9700
2. If they can't cure it because the wheel is damaged, the machine will show it.
3. Besides the rotor cleanout, you might have some success with cleaning the inside of the wheel itself. Some dirt here, a little "marble" there, pretty soon it adds up. More so on 18".
Good luck.

User 4221

Has anyone considered wheel bearings?
Do you get popping noises over small bumps as well?

CAHRERA

Mine is smooth all the way up to 80 mph. When I get to 90 and above it has a slight vibration. Not sure if it's wheel balancing or what. Interesting to see so many folks having similar issues.

g_murray

I concur.
An 'ever so slight' vibe in the steering wheel from approx. 50mph onwards that doesn't get better or worse as I go, say, past 80. Doesn't bother me - drivingwise - but I've made a mental note to get all 4 rebalanced again.
("Excellence is expected" ....right?)

I _did_ click on the gsp9700 weblink (thanx for posting this!) and have located a whole bunch of 'shops' with this unit (here on Long Island).
Plan on visiting one on Sat.

Latah,
G.

TomF

I had the same symptoms and tried all of the above as well. It turned out to be the tie-rod ends. The tie-rod ends do wear out and they are really hard to detect. The rubber inner ends crack and are nearly invisible to see. I wish that I could post a picture, but every pic that I take doesn't show the detail enough to make the cracks visible. Run a search on tie-rod ends and there are more details. I believe that any 993 with over 50-60K miles should have these ends replaced. They are really very weak, especially if you live in pothole H%ll like I do.

Evan

Tom - did you have uneven tire wear (front) when the tie rod ends were worn out? Insides worn bad, outsides tons of tread.

TIA

tam993

Took my 993 to a speed shop, they checked everything and then balanced the front wheels "on" the car.
haven't had the problem since.

Evan

tam993

Where did you have that done and "how'd they do that". On the car. never heard of that being done before.