When I bought my wife's XKR, it had brand new tires (Continental Constant Contact Sport DWS) and I noticed that it pulled a bit to the right. After about 6k miles, I finally found an indy within 50 miles whom I really trust. He replaced the right ball joint and contact arm bushings, and he took it to his preferred alignment shop. Both front tires looked fine at that time. It has felt perfect ever since through another 8k miles.


Yesterday, I decided to clean the wheel sensors to solve intermittent ABS and TRAC warnings, and when I pulled the front wheels, I was shocked to discover that the inner edges of the tires are worn down to exposed steel belting equally on both sides. (All three DWS wear indicators are still fully in tact.)


My first thought was that they set too much negative camber, but research on the forum tells me that camber is not adjustable on an XKR except with shims and should not be a problem. Have I read incorrectly? Did the alignment shop mess this up? Should I complain after 8k miles? I suppose I should have caught this sooner, but it's almost impossible to see this inner-edge wear with the wheel on the car.

I have the impression that front end alignment is more of an art than a science...


Thanks all.

 

The problem is negative toe. Many shops that deal with imports have a spreader bar that loads the front wheels to point out, then set some positive toe. I think if you have the shop set for close to max. toe in it should be okay.

 

Might pay to check the top arm bushes for wear this can cause excess camber.

 

Check the ride height. This is what sets the camber. Either your shock mounts are worn out (Very likely, and the Jaguar replacement part fails, too!) or the lower shock joints are bad. Or both.

Check the Vehicle Spec Book on jagrepair.com for specifics on the ride height.

 

When were the upper shock mounts replaced? 90K miles and 16 years, no way they are not crushed flat.

 

^^ I agree with what has already been said about restoring the car to its proper ride height. You do that with new upper shock mounts, and it is a good idea to replace the various bushings while you have the suspension apart. Once you do this, the car almost always returns to the proper camber specs....

 

I too had badly worn tyres on the inside edges on nearly new tyres despite having the front end toe in/out checked at the time of fitting. I found that the front suspension was sitting about 1.5 inches too low compared to the original spec.

As fmertz said, this will throw out the camber angle leading to rapid extreme tyre wear. My problem was due to badly sagging front springs which I replaced along with all bushes, ball joints and upper shock mounts.

May I add that if your ride height at the front is very low, just replacing bushes and upper shock mounts will not restore the full ride height, you must replace the springs as well.

 

You can also add a 3/8" spacer on top of the shock mount. Worked well for my 97.

 

Mine is an earlier car, and I have no direct knowledge, but I believe that on later cars (post 2000 ish ??) - the rear lower suspension arm bolt is "eccentric" and can be used to adjust the camber angle. (I think it is recommended that earlier cars are fitted with this bolt if the lower arm is replaced or re-bushed.)

Is it worth getting this checked ?

https://www.jagbits.com/mm5/merchant...Code=JZB100086

 

The eccentric lower fulcrum bolt came in with the X300 1993/4 not sure that it would have too much of a bearing on the inner tyre wear of the front wheels.

 

I have just corrected the opposite problem - bad wear on the outer edges of both tyres. The issue was toe, it was way out.

 

Not sure about dates - it's not "standard" fitting on a 1997 X100.

 

Thanks to all of you! It's amazing how much education one can get in a few days from a question on this forum. I will do further research and assess the ride-height, and then I will go back to my indy with questions about shock mounts. I was told that all the bushings had been replaced just prior to my purchasing the car (?) and when my indy replaced the right ball joint and lower arm bushings, he said he had examined all the other suspension bits and they did not warrant replacement.

 

My remaining question is whether to blame the alignment shop and expect them to make amends after 8,000 miles. In all other respects, all four tires look as if they should have been good for at least another 15,000 miles. What kind of mileage do you all get from Continentals?

 

You can only blame the tyre shop if you asked for a full alignment check including camber angle. Checking the toe in/out measurement does not include a camber angle check.

Firstly, check your front ride height against the original specs to see if your front end is lower. The measurement is from the centre of the wheel to the wheel arch lip in a vertical line. The further away from spec you go, the greater the camber angle will be out and the quicker your tyres will wear out on the inside edge. I will look up the correct distance.

The front end on these cars are very heavy and sagging springs, worn bushes and crushed top shock mounts are very common. As DevonDavid and Frontman25 said, I believe you can fit a eccentric lower fulcrum bolt in the bottom wishbone to slightly adjust the camber angle but the correct way is to replace all the worn parts to restore the cars ride height. You can also put spacers under the front springs to help increase the height.

 

Just had a look on JTIS, the correct front ride height at curb weight is 400 mm +/- 15mm or for the old school it's 15.74 inches +/- .59 inches. Surprisingly it's the same on a XK8 or XRK.

 

When they say "Apex of Whel Arch", does that mean inside the wheel well or the exterior edge of the body?

 

The classic measurement is from the center of the wheel cap to the edge of the metal fender lip directly over the wheel....

 

OK, my ride height is 15.25 inches identically on both sides. That's low, but given the margin in Andy's post above (+/- .59) how badly out of spec is it?

 

You are close to normal....