Hello Cats,

I noticed some wheel shake at about 70mph and thought the wheels might need to be balanced. I took it to a tire shop to have it done and was told that I didn't have a wheel balancing problem but it looks like I have a suspension problem. I was told either the shocks or the struts were the issue. They showed me the tires and the driver side front tire is showing uneven tread wear on the inside portion. The passenger front also but not as much.

Has anyone had experience with this issue? Looking for what my next step might be.

 

On the front end, the upper suspension bushings could cause tire wear like that. If they get worn out, the suspension could have some play in it which would cause the tires to "toe out" while driving. That would cause wear on the inner edge of the tires. You can check that by lifting the front end and trying to shake the tires from side to side. If it moves then it could be those bushings, or maybe the tie-rod ends on the steering.

I'm trying to think how worn shocks/struts could cause tire wear like that. It doesn't make any sense to me, but like I said, I'm no expert. The shocks just dampen the up and down motion, and even if the shock was worn out, or the bushings were dust, the rest of the suspension parts would still keep the wheels pointed in the right direction. But what do I know?

 

wheel shake at that speed, in my experience, is one of two things...out of balance, or a bent rim.

These cars require a force-balance to be at their smoothest, a regular spin balance does not get the weight as finely tuned as the force...you'll pay an extra $10 a wheel, but WELL worth it.

Even if the shop tells you they balanced your wheel to near perfect, if there is any deformation in the rim, no matter how small, you will feel it...and feel it at high speeds. Look for any damage, and if any is discovered, pay the $125 to have it refinished/repaired to round once again...then $17 for the force balance.

After that, your inner edge feathering is as Sam pointed out - too much toe out. If there's play as Sam explained how to diagnose, it could be either the tie-rod end, or the upper wishbone bushings. Both are DIY projects (sam has a video on the uppers, can't get much easier than that for instructions) and the upper bushings are not that expensive either - $60 Tie rod ends are cheap too, $30 for a pair, and slap those puppies on yourself, and get an alignment done...be sure to use the dealer, or an indy shop with jag experience in suspensions, because as i have found out, NTB and other 'tire joints' just don't know how to put a little load on the tires to simulate driving, before setting toe. Machine will show in spec, but in the end, the toe gets too far out when actually driving it.

 

Well said Matt. I have had very similar experience. The inside of the rim especially can be deformed from potholes. A roadforce balance is the only way to go on these cars.

 

This thread caught my eye. I've noticed the same shake at 70mph in my '06 XKR. I replaced the rear tires earlier this week and the shake got quite a bit worse. There was some uneven wear on the rear tires and I think that now that I have fresh tires the issue is no longer masked and I'm feeling all the vibration. I was planning to get an alignment when I can hunt down some free time.

 

Thanks for the info Cats. I'm on my way.

 

Do you have a source for the $125 wheel repair and the "force balance" ? Where can I get this stuff done ?

 

My local Discount Tire contracts it out to a wheel refinisher...they pick it up from Discount Tire, then returns it the next day all fixed up. Just call your tire shops and ask if they offer a wheel refinish/refurbishing service. If that fails, the Dealer usually hires similar companies to do it also, but it'll be a bit more expensive, probably $25-$50 more each wheel.

 

Thanks for the wheel tips; i'll give it a try. What is a "force balance" and is it something all the dealers do ?

 

http://www.gsp9700.com/pub/technical/4202T/5THEO004.cfm

http://www.gsp9700.com/pub/features/how.cfm

Only some shops and dealers have roadforce balance equipment.

 

Force balancing is when the wheel is balanced while it is pressed against an object that simulates the road surface. That allows the tire place to balance it in "real world" conditions.

LOL! WhiteXKR's explanation is better than mine.