2002 xk8 39,000 mi- Shimmys bad at 70 plus mph. Reduced tire pressure from 45psi to 25 psi per member recommendation and jag specs for
Factory Continental tires (New) Result: No noticeable difference in ride or shimmy . Next, balance and alignment. Result. Very slight improvement. Next: New front and rear shocks,mounts,lower ball joint,control arm bushings and realignment. Result: Much improved ride , some reduction in shimmy but not by anyones standard acceptable. Mech says probably flat spot in tires. (I doubt it) $2300 later still shimmys. Anyone?

 

Where do you feel the shimmy? In the steering rack or in your butt or gut?

 

steering

 

Several of us had a vibration that would not go away with balancing. Many then had them rebalanced using the Hunter Road Force balancer and the vibration was cured.

I had one wheel that still did not respond and replaced it. My theory is that the machines all mount the wheel using the center bore and the five lug holes were slightly eccentric.

 

ussintrepid;
Where in the world did you get the idea to put 45# in your tires? Maybe on a 3 ton truck, but not on a passenger car. Anyway,
Are your tire wearing well? If you run your hand over the enter edge and then the outer edge of the tire in one direction then again in the other direction, do you feel what could be considered rough edges. If so, find another alignment shop and for gosh sakes, if you have 45# of pressure in the rear tires get that down to at least 32 #s maybe 35.

Cheers

 

ussintrepid;
Another thing, you say your mech said probably flat spot in tires. If he's worth his salt at all, but can't tell if there are flat spots on your tires, time for another mech.....
You may be, being lead down that old road of give me more money. I don't really know what I'm doing...

Cheers

 

Are the tires original? If so, you might want to take a second look. Check for any type of blistering. I had an internal steel belt brake in a tire once, and there was a shimmy like this. The only fix is a new tire.

Separately, try and find out if one of the wheels is bent. I would do as RJ suggested. Find a reputable alignment/balance place and let them check the wheels out. You might want to reach out to the local Jaguar dealer as these guys invariably have these used cars coming in that sometimes need these types of services. They usually know of this one local place that buys the most expensive machines to stay on top of that market.

Alternatively, if the problem is bad enough, you might be able to find out by yourself. Lift the car up one corner at a time. Get a machinist gauge, somehow mount it, and spin each tire to find out if it is out of true.

I have this: 1-inch-travel-machinists-dial-indicator-623.html

Best of luck, keep us posted.

 

I have dumped the mechanic and the 45 psi was his recommendation not mine but I do think 25# as recommended by Jag will promote tire wear. By the way ,tires have less than 200 miles. Will have tires rebalanced using Hunter Road Force.

 

I agree that 25# will wear out tires rather quickly; probably why Jag dealer suggested that so they can sell you more tires.

Anyways I suggest 32-34 psi cold.

Probably a bent wheel. Does not take much of an impact to put a dent in aluminum wheels. When you have wheels balanced ask the tech to look for any dents in the wheels before mounting tires.

I did have a set of P-Zero's that two of the tires had slipped belts in them. Always had a bit of a shimmy until I finally just got rid of those tires.

Road Force balance did improve the P-Zero's shimmy, but did not eliminate it.

Best of luck.

 

Grooved pavement makes mine shimmy. There is a LOT of feedback on the rack.


Every time mine has shimmied, I've focused on the road and saw grooves that match the steering wheel movement.