My Jag is stored in the garage for the winter, and I'm looking into a suspension issue. The front tires wear too much on the inside, even with regular tire rotation, which I do every 5,000 miles. The shop I took it to did a four wheel alignment, and said that the camber adjustment was maxed out on the front end. He did slightly increase the tow-in which he said would help a little. The car drives fine, and always has, but the tire wear issue is not insignificant. Not horrible, but not normal.

I measured ride height. All four corners are about 14" or thereabouts. My research shows that it should be 15.75". It does not look like the springs have been cut to lower the ride, but it is possible. I suspect the springs have sagged due to age. I know that ride height affects camber, especially in the front. Not sure about the back, but I don't think it affects camber in the back. Nonetheless, I would want all four corners to be within ride height specs.

I would replace the springs, but I have also found that the XJR OEM sport springs are no longer manufactured. You can get new OEM comfort springs, but not sport.

Will brand new comfort springs restore the correct height? I would get sport springs, but they are no longer available. Used ones may or may not be any better than mine. I do not drive terribly aggressive, so I'm not opposed to using comfort springs if they will in fact fix the ride height issue.

All thoughts are welcome about how to correct the uneven tire wear and/or ride height.

Thank you

 

1. Common knowledge is that the inside tire wear is more caused by toe-in, then by camber.
There were some interesting discussions going on some years ago, setting the toe-in to the max, while using a spreader bar on the fronts to do so.
You can try to look them up, a member called 'Brutal' was leading them.

I had the exact same problem on the original tires on my car (down to the thread, but only inside, and hard to notice), it seems that following the above instructions solved it / reduced it so far.

2. Ride height is not as high as you mentioned, see the below Jaguar information.
Yours is a XJR, if it came with the ROW springs, it is pretty much spot on.

What I experienced though is that failing shocks let the car drop.
I know it should not be, but it does, and mine dropped about an inch.
https://www.jaguarforums.com/forum/x...d-inch-176869/

I probably had a bad one already on the left (and some unexplained ride height differences for a while), when the right side failed it was kaboemmm.
Fitting new shocks brought the car back at 14.1" all around.

 

I will second the shocks holding the car down, I had an XJ40 that I replaced the front shocks and the ride height increased by about 15-20mm

 

Yes, that was the chart I had found. I wasn't remembering the numbers right though. The shocks are relatively new, but I found that they are comfort shocks, not sport. The reason for that would have been my ignorance at the time I bought them. I probably did not know there were different shocks. I will monitor the situation with the new toe-in adjustment before doing anything else. If that doesn't work, I may revisit the shocks. Thank you for the input.

 

Hi Eric,

One commonly-overlooked cause of excessive wear on the inner edges of the front tires is worn suspension bushings, especially the lower control arm bushes. When they perish, they allow the front wheels to splay, resulting in tire wear that is similar to that produced by excessive toe-out.

Also, along the lines of Eric J's and Robman's experience, I've found that ride height is lost when the shock absorber top bushings compress over time. It makes complete sense to me on the rears, where the large "donut" spring isolator, part 5 in this diagram, represents part of the overall height of the spring/damper assembly:




What doesn't make sense to me, but I swear it seems true, is that when the front shock upper mount bushings compress as they age, some ride height is lost, even though the springs are entirely separate from the shock and the bushings in its upper mount, Part 8 in this diagram:




Cheers,

Don

 

That's correct, and I kind of assumed that the OP had checked on play.
On my car, all wishbones, arms and other rubbers were replaced just before I bought the car, so that might have contributed to it indeed.

Because these cars do not ride on the balance point of the shocks (the stable point between positive and negative travel of the shock), but on the positive side.
Hence the shocks help pushing the springs out, with a increased ride height as the result.

 

Alignment IMO is dealer only on these vehicles ....make sure they have an old-timer who knows how to do it. If something is wrong .. they can tell you.

It's also not expensive.

 

A couple of thoughts: pretty flat in that part of Ne, so a less aggressive suspension will probably work well. If you think the springs are collapsing, go with new comfort units. Bilstein green shocks will give a firmer ride up front, but still comfortable. New upper front shock mounts are now available and affordable that will help, as well.

I had the "best guy in Hampton Roads" working on the alignment of my X308, ok, but then I got a coupon from the dealer: much better, truer tracking, less tire wear and incredibly better job of balancing the tires.

 

Thank you all for your help. A couple of you have mentioned having a dealer do the alignment. Is that because they better understand how to set it up? Or is it because it takes special equipment not typically available at third party alignment shops?

Thanks again, I appreciate the input.

 

Don't think so, it needs a guy who knows what he is doing, either at the dealer or an independent, no Jaguar specific equipment needed.

And a little understanding on your side is a pre, just to check the process and outcome.

They normally make a print before, and after the alignment.
Each setting has an acceptable value range for each wheel / each setting.
A normal mechanic will set them in the green, wherever in the range, a dedicated mechanic will set them as much in the middle as possible.

But, front toe-in should be on the max for our x308, if you believe the stories ..

 

I think that's right. The advantage the dealer has, with an older tech or two, they have seen lots of Jags in various tire and wear ranges and have a sense of where to best make the settings. That, and the fact they are usually working on the high end of demanding customer and incomes.

That said, best alignment I ever received was on a Cadillac at a Firestone dealer . . .