My 2002 XK8's Coupes' new tires wear wore unevenly (inside tread wearing much faster than outside) after having a four wheel alignment...this after the shop called the dealer for the caster and camber numbers!

I remember a thread about how Jaguar finally changed the factory specs...where would I found the proper specs...apparently even the dealers do not have them.

Thanks!

 

yes we dealers have them and no the specs were only changed on the 03 and up Stypes. and should have been on the 04 and up Xj's. youre issue (if nothings bent, or wornout) is the alignment was set to the middle and if you dont allow for tollerances, play and wear when doing an alignment. youll end up with this. ask them to realign and push out on the inside of the front tires to take out movement, and watch were the toe reading go. this is what the road does to your suspension as you drive, it toes out the front tires. Many times I end up toeing the front tires in so much theyre in the red out of spec, but when you simulate what the road will do, they go right into the green and middle. And by seeing tire wear thats even for the life of the tire if nothing hit like a curb or bad pothole, it works perfectly. If theyde have done this to start with (why Mercedes wants alignments done with a pressor bar) theyde have found that your tires "toed out" into the red.....that why the insides are wearing. the machine is a tool, not the end all. as Ive said before, you have to "KNOW" what your doing with a tool, and when I align the same cars and see them again every 5k, I know what works with alignments and what doesnt...If more tech realised you drive a car on the road and not the alignment machine, theyde do a better alignment

 

What about camber, do you 'anticipate' weight transfer to the springs and take the camber in in more towards the red also brutal?

 

Have the lower control arm bushings checked for cracks.

 

only if youre REAAALLLYY fat...
and then if your gonna road race or SCCA youll need to weld in camber plates (if allowed in class) to dial in enough neg camber to heat the tires evenly enough(flat contact patch) across the face. as measured with a tire pyrometer(I use a infared temp gun)
theres no caster/camber adjustment on XK's without 1 taking the suspension apart and moving shims up top, or using offset bolts. But these affect too little with regards to an alignment on the XK and you would use them if your trying to offest damage and really wornout parts (like upper strut mounts), Then why not replace or repair properly. Your biggest wear angle is always toe front and rear, camber has to approach 2 degrees +/- before this induces wear, castor is not a wear angle..

 

You tell 'em BRUTAL!! I never set the toe to factory spec on the S, XJ, or XK. I always set the toe in until it's red. It stops the excessive wear and also calms the wander you get with the big fat tires on uneven road surfaces.

Just step back and think about the alignment specs for a minute. The camber is speced as negative which means the tires are leaning in at the top, looking from the front of the car towards the windshield picture a letter A with the 2 uprights your tires. Now add to that even a tiny bit of negative toe, picture yourself laying on the bonnet with you head towards the front bumper your tires would look like a letter V. Now, which part of the tire do you think is going to wear first?

What all this means is screw the specs and have an alignment done by someone that knows what he's doing.

 

or she....

 

Good tip to know, thanks both of you yahoos.

Since I have had my lower shock bushings, upper shock mounts replaced and new tires installed, the dealer did an alignment. Now after 15000 miles, I checked the tire wear today. Nothing noticable driving, but here is what I observed:

I = inside C = center O = outside
------------------------------------
LF - I 8/32 C 8/32 O 8/32, no noticable tread problems
RF - I 6/32 C 8/32 O 9/32, slight feathering on the inside of the tire

LR - I 8/32 C 6/32 O 8/32
RR - I 8/32 C 5/32 O 8/32

on the rear, pressure was reduced recently to 31 psi to help wear (was at 32)

Any ideas on that RF? I am going for an alignment tomorrow, before it gets any worse. Will take my 'toe in' advice and apply it as well.

 

Your rf toe is too far out, i look at tires alot for issues and if there more than 2/32nds diff between the inside and out you need an alignment. Never matters if the vehicles tracks straight or not, tire wear is whats important, i can have a car drive perfectly straight and have steel sticking out in no time on the edges. On your center wear, i know alot of people think over inflation does this, which is true. And what i see more of is it depends on the tire type as well. Michelin pilot sport a/s are the absolute worse ive seen for this. They wear out the centers showing cords and the inner and outter trad blocks still have more than half the tread, and since im the 1 servicing the car i know the tires arent overinflated. This is 1 reason i never rec. These, along with since theyre dirrectional you cannot swap side to side to correct a tire pull, you have to break the tires down and flip on the rims....anf waterboy, i hope these arent yours cause they are used alot on xk's

 

Thanks brutal for the eval, i'll do the alignment tomorrow. I put on some Falken FK452s, and they're holding up pretty well. I've got another 20k miles left, i think. Directional though... so I may have to swap sides on those front ones.

 

I hate directional tires as well and see no real preformance advantages. I have no problems with inner/outer treaded tires as they can be swapped side to side without dismount/remount/balance issues. My 30 years experience doing alignments says 90%+ of pulls are caused by tires rather than alignment issues. It's easy and cheap to swap wheels and tires side to side to diagnose this. It's a PITA and expensive to dismount/remount/balance a pair of 20s just to diagnose a tire pull. I'll usually just put 2 wheels and tires from another known straight driving car on to diagnose the tire pull rather than spend an hour and a half f-ing with the directionals and charging the customer another wad of cash to tell them they need to spend another $1000 to replace some tires that don't go straight.

 

Hey Matt,

I tried to browse for the previous camber numbers you posted, but the archives wouldn't get me that far back. Do you still have them from the prior alignment?

 

lol, thats why I ask " is it a drift or pull, there is a difference, a pull is where you let go of the wheel and turn on the turn signal cause you are changing lanes" and yes these are mostly tire issues. Also if directional Ill swap to diag and drive the customer to show them. Then ask them the $$$$ question on what they want. most just opt to live with it at that point, but at least then they know....

 

Andy, previous camber is as follows from June 08

LF -0.5 deg
RF -1.0 deg

I got the alignment done today, and asked for a toe-in in the red, if possible. Instead, i got a LF of 0.18, and a RF of 0.2. Isn't that setting the toe out? I am getting the + and - mixed up.

BTW, according to the pre-alignment sheet, my LF was a -0.03, and my RF was a 0.11.

Camber is now at LF -.06, RF -1.1. That's 0.1 greater than 8 months ago. Its a lost cause!

 

Well mate, in my opinion the negative 1.1 degree camber is the reason for the inner shoulder wear that you measured on that tire.

Ask the guy who set up the car whether the car is set with toe in or not/ Brutal is right, the forward thrust when you are driving ads up all the compliace in suspension bushings and ineer/ outer tie rods to force the front wheels towards toe out.

The only number that matters is the total toe in for both wheels. And that will have to be reset after the camber problem is corrected.

 

Andy's right I was looking at your toe, while the camber is negative, I think the soft upper shock mounts are collapsing on yours. This drops ride height slightly and drops camber more negative and creates more negative roll in corners to the left. (It roll over more on the inner shoulder cause its not being controlled adequatly)...Of course like Jagtech always says, this is purely conjecture on the web without seeing in person.. The right side always seems to go first and I think its cause the right is exposed to more potholes/roughness on the right edge of most roads. Are you planning a trip to Houston this year? come by and Ill look at it and align for you for free call it a JF discount if you drive down here....just let me know

 

Hey Brute,

Agreed on the right side suspension wear, I see that alot up here particularly with ball joints on older cars. I think Matt said he had his upper strut mounts replaced, and the recommendation at the time was for new springs too.

Matt,

As best as I can tell, offset lower arm bolt might get you .3 degrees of adjustment. That's probably worth it to me if I am keeping the car, as it should roughly cut the uneven right front wear in half. I'd still be reluctant to throw springs or upper control arms at the car: that's fat stacks of cash, and the final settings might reveal that you didn't get much bang for the buck.

One final comment from me, I'd characterize your tire wear as quite acceptable given the mileage on your current set of tires and the tread depth still remaining. Maybe just keeping the toe in set correctly and saving the money for the next set of tires in 15K is the most prudent approach.

 

That's right Andy, they did 'suggest' new springs when they replaced the upper shock mounts. But, I declined. (fat stack as you put it) Is the lower arm bolt the same as the eccentric bolt? If so, that was added by the dealer during the big suspension fix. My camber may be a lost cause w/o the new springs.

BTW, inner edge on the driver side is feathered as well. If I get another 10k miles on these tires without the road noise getting too bad, I suppose I should be content and just accept it.

Brutal, I bought my car from your dealer. I bet my sales guy is still there, Richard I think his name was. Greatly appreciate the offer to take a look at it! I drive down to Conroe alot, but on business, so I would have to make some time to go into Houston to see ya. I'f I do, i'll drop by.

On a tangent, did you know a guy in the service department that bought my/our trade-in, it was a white chrysler minivan, about 2 years ago? If so, i found the spare remote! When I tried to call about 6 months ago to find him, they told me he had left.

 

Yepper, the eccentric lower arm bolts get you a little more positive camber and you're already there. The springs are a trial and error deal, and if they raised the front ride height enough to reduce the negative camber, it would be reasonable to assume that the car would then be sitting low in the rear.

 

And how goofy would that look? <rhetorical>