I hadn't noticed this until I happened to be in my wife's car this morning and backing out of the garage. I noticed a dark "scar" along the inside edge of the left rear tire. It feels almost like a piece was cut out and seems weird. Can anyone tell me what caused this and what needs to be done?

Thanks,

Doug

 

Ran across a rock or anything else on the inside edge perhaps?

If not through to the belts, I'd let it scuff out.

 

Run across something.

There's lesser marks round the outside edge (red arrow). Must be recent or these would have scuffed off with driving:



Also what appears to be a thin cut running round inside of this (blue arrow).

With tyres, what you can't see is frequently more significant than what you can see. The "scar" you arrowed looks minor but the only way to be certain there's no damage to the structure is to have the tyre removed for inspection.

Graham

 

I had something similar on my Pirelli rear tyres except both rears had splits (deep ones) around the inner edge only despite 6mm of tread on both tyres. I binned them and fitted AVON ZZ3 on the rear, that was 3 year ago and seen nothing like that since.
However your picture does show "wear" on the inner edge as opposed to the outer edge, might be worth having it 4 wheel aligned to be sure. TS

 

Does she have an affinity for backing into and running over curbs? That would be my top suspicion with no further details....

 

I am the only one who drives the car and it typically only goes a few miles a day. The closest thing to dropping off a curb are the very rare times when I leave the driveway at work and I cut it too close. But that is always the right rear tire and the "drop" would be maybe an inch or so.

I was more concerned about the wear pattern on the inside but couldn't see how that would have caused the "scar". I hadn't noticed the slight thin "cut" along the outside but will look closer this weekend.

I bought the tires in 2013 (Hankook) so they don't have all that much mileage on them (about 5,000 a year max), and the fronts look just fine. I was thinking about passing by the local shop where I bought the tires for them to have a look.

Doug

 

Looks like the tires are rubbing, is your car lowered?

 

Car is not lowered to my knowledge (see attached photos). By the way, that thin line is apparently part of the making of the tire since the exact same line is also on the passenger side rear tire.

 

Good taste in colors i see

 

Nice. How did you get the photo to be so large?

Doug

 

Went by the local tire place today where I bought the set in 2013 since this tire was losing air on a regular basis. So they pulled the wheel and found a nail and were going to fix that for free (I had the road hazard warranty). But then I pointed out the gouge (which looked even weirder once the wheel was off) without hesitation the guy said the tire is not safe and I needed another. They glanced at the right rear and said that should be replaced as well since it was also wearing on the inside (not sure if there was a gouge or not). I asked what could have caused that and the guy said probably alignment. I can see that causing a complete uniform wear around an edge but the gouge still seems like a mystery.

Anyway, I figured might as well get both rears replaced and am doing so on Monday, along with an alignment.

Doug

 

Got the tires installed and they started doing an alignment. Of course nothing is easy on these cars and it turns out I need some special "eccentric bolts" (also known as camber bolts) for the front. The rear also needs aligning but somehow no special parts are needed. The bolts need to come from the local Jaguar dealer and these are something like $60 each--insane. An alignment that normally takes less than an hour on most vehicles turns into several hours on the Jaguar.

Oh well!

Doug

 

Typically, when the front camber is off, it is a red flag that the ride height is off. Check the spec book on jagrepair.com, there is a specific height between the center of the wheel and the fender. Generally, this is due to a collapsed upper strut bearing (stock ones are junk), or possibly a bad lower strut bushing. Before spending money on the wrong thing, check these items so you can restore the ride height, and bring the camber back to spec "through geometry".

Best of luck, keep us posted.

 

^^ What he said....

 

+1 on the previous posters. It is ride height related.

 

I'm dropping it off tomorrow morning since he received those eccentric bolts from Jaguar. Funny thing is the workshop manual says that only the early vin numbers did not have those bolts so I am wondering why needed these. Anyway, I will point out the ride height thing to them.

Doug

 

By the way, I quickly did the ride height measurement at the front wheels and the ride height is low (about 14" or so). The rear measurement is more like almost 16". However, this seems to be a not uncommon situation with these cars--found this thread where the OP had similar measurements initially and also after doing a bunch of bushing work (see his post #16).

https://www.jaguarforums.com/forum/x...ont-end-23290/

Also what confuses me is how is this really related to camber adjustments. You have the basic chassis to which the front end is aligned against and the body is supported on the chassis. So what difference does it make to the chassis if the car is higher or lower on the chassis?

Doug

 

For ride height, always go where the data is. Check page 44:

vsb_09_2009.pdf

The design is called short-long-arm. The lower control arm is longer than the upper one. As the load on a corner increases (as in a turn), the body rolls and the suspension compresses. The idea is that the short arm tucks the top part of the wheel back inboard (increases negative camber) so that the tire remains more flat on the road.

Here, when the upper bearing collapses, both control arms swing up, and the same thing happens (resulting in negative camber at rest).

Hope this helps.

 

It's the way the geometry works, as the suspension goes down negative camber increases, as it goes up it decreases, and may even go positive.
This is done because during hard cornering the outside suspension compresses, increasing the negative camber helps keep the tire tread in proper contact with the road surface by preventing the tread from tucking under, and maintaining tire grip.
Regards

 

But I am not clear as to how the ride height has anything to do with the camber adjustment. Anyway, the car is at the alignment place now to have the eccentric bolts installed. Told them just to do the best they can.

Doug