I just bought a '04 MCS with 108k 6 sp man. I had the alignment checked and put new tires on the front. Here in Boise we have some new concrete interstate and the hiway is grooved. When I drive on these grooves the car shimmies. If pavement changes to asphalt or concrete w/o grooves no shimmy. Also I have a Chevy 2500 that travels these same roads with no shimmy. Would love to hear your thoughts on this matter.

 

What type of tires are you running? Runflats or conventional? I had the same problem - fixed after I replace the runflats. Also, are the front and rear tires the same brand and model?

Kevin

 

These grooves will also cause a slight shimmy if the tires are underinflated.

 

Kevin, the tires are different brands front to back. Front is a firestone and back is a Hankook? they are conventional. V rated the tire dealer informed me. same size front to back.

 

Thanks Nimbley I will Check the pressure as well.
David.

 

what you are experiencing is called trammeling (google it)

in short description it is a tendency for the tires to follow the road grooves.

wide performance tires display this more than 'standard' tires. When I had an 02S with 17's and Pir' run flats I experienced this A LOT. Changing tread pattern helped a bit not but as much as when I changed to 16" wheels with narrower tires . . . and I now live where I don't experience grooved roads!

 

My guess is you need lower control arm bushings. They go bad and you can wander.

Tires would be my second guess, but at the mileage and how bad it is (so bad you post here) bushings sound right.

It isn't a terrible job, but bigger than some. Many upgrade to power flex bushings. Just search LCA and read away.

 

Another vote for LCA bushings. At 108k, it's probably time. But the tire thing is true, also. Even though your 2500 has wider tires, they are probably E rated, and I'm guessing you are running 70 to 80 psi. A world of difference from dinky little passenger 195 or 205s at 40psi.

 

I vote for control arm bushings too. Mine are shot with only 60k miles on them.

 

for what it is worth my experience was:

yes, I replaced lower control arm bushings with PowerFlex poly' around 60,000 (on my 02-S)

but that had no noticible effect on the trammeling.....

by that time I'd replaced the Pir' rf's with a set of regular Yoko's which helped some but I saw no significant change when the bushings were replaced. Wide flat tires was the best reason I could come up with . . .

my 2 cents . . . your opinion may vary.