400 E shimmying. Boring, but unsolveable
 

2 sets of tires, wheels checked for bends, rotated and balanced 4 times. They were r&b'd today, and the shimmy got worse. Unless I've got a wheel that is bent and they missed it on the test, it's something else. But, what?

at what speed does it come and go ??


feel it through the steering wheel or the seat ??

Were the tires on there long enough to show any unusual wear?

I am thinking tie rod ends or idler arm, if you have indeed ruled out tires and wheels. Other possibilities include warped front rotor with sticky caliper. Of course there's always the flex joints.

Can you be more specific about the shimmy, what speeds it shows up at, and how you feel it?

Nothing is unfixable.

Were the car mine I would begin by raising the front wheels safely off the floor and performing the four P's (push, pull, pry and prod) on all joints and suspension members. That costs nothing. If I find something loose I replace it.

If the suspension is found to be tight, the next thing I do is go to www.gsp9700.com to find the nearest shop with a Hunter GSP9700 wheel analysis machine. This is more than a wheel balancer. It has a pressure roller that looks for Road Force Variation(RFV.) This is a fancy term for stiff spots in the tire. One of these computerized tire and wheel analysis can confirm or deny that the problem is wheel/tire related, and in some cases balance the tire to compensate for it.

Another thing would be if you have a buddy with a similar car that you could take all the tires and wheels off of, mount them on your car temporarily and go for a ride.

All this said, in the vast majority of cases such issues are wheel/tire related, but until we get some more details, we can't do much more for you.

I had a similar problem with a quattro. Bought new tires/wheels, had them indicated / checked for lateral and radial run-out, true, still had the problem, went through 3sets of rotors and pads, finally four new hubs and bearings cured it (warranty).

I had a similar problem on my 300se...turned out ot be front wheel bearings...

Yes, the wheel bearings are one of the items that need the 4 P's applied.

Wheel bearings could probably stand to be re-packed. Good idea

New rotors, vibration in wheel but can feel in seat too a little, 40-60mph, gets a little better the faster you go

My indie is the most reputable in 100 miles, and also the most expensive. They check all this at minor service intervals, every 5k. I have an appointment for the 15th to have them take an extra-deep look at all bushings and components. The car does need new shocks. I'm swaying to the side over bumps and it feels like the tires are not making the best contact with the road.

If nothing else works, it could be control arms. I did not see how many miles you have, but if the control arm bushings are worn out, this can cause shimmy.

Rgds,
Chris W.

If I told you there is a decent amount of steering play, would that be a secondary issue, or separate one? If secondary, to what dioes that whittle it down? At higher speeds, as the shimmy calms down, on the straights, it becomes more evident when I turn the wheel, merging to another lane.

BTW, these are 17" AMG AeroII wheels, OEM, non-staggered. Mich. Pilot Sport A/S Plus tires, no unusual wear

Steering damper? Easy DIY.

done 7k miles ago

if these aren't mich. pilot sport II, tires are suspect, as i think MB had a bulletin out to not use the ps I on MB's

shimmy from balance usually @ 50-60 and disappears @65-70
problem in front, feel it thru the steering wheel ~~~ problem in rears, feel in thru the seat

belt break in tire appears at slower speeds

if all is tight, i would find someone with a hunter roadforce balancer that knows how to use it

Thanks for the input, but this has happened - as I mentioned - on 2 separate sets of tires, different brands.

The memo was for Pilot Sports, not A/S, not A/S plus. It pertained to later-day MB cars because owners were complaining of issues related to excessive tire wear and noise. None of this has anything to do with my car

I travelled 36k silent, smooth, sticky, trouble-free miles on PS A/S on my previous 202 with zero issues, and ample tread remaining.