Prior to fitting 4 new tyres I noticed that one of the rear tyres was wearing badly on

the inside edge so I took it to a recommended suspension specialist.

Really pleased I did,he gave me a master class!

We had a look at the suspension underneath and he said it was very much a

Ford set up which I was not aware of to be honest and he confirmed that the

camber cannot be adjusted although after adjusting the rear toe that

improved the camber somewhat.

He found that one side was +4mm and t'other +14mm!! No wonder the tyre

was wearing badly.

He adjusted the front wheels and showed me where the adjustment was ie two

eccentric bolts on the straight and curved control arms.

I have been running the tyres at 30 psi for years but he recommend 44psi!

The tyres are good for 50 psi max and 44 will reduce tyre wear and reduce

petrol consumption.

The ride is harder but I am giving it a go.

I think I got my $100 worth!

The moral of the story: Choose carefully who you let loose on your Jag!

 

Keep an eye on your tires, if the center starts to wear you should reduce air psi to sticker specs.

Specs are:
Rear tires at 100mph or less: 32 - 36
Rear tires at 100mph or more: 34 - 38

 

50 psi seems to me much too much!
You will have indeed a tough ride and wear on the center. would only be advised if you have a very sporty ride

 

44psi is on the tyre sidewall and only recommended for "max"payload. Of which you wont ever hit unless you have some really big people in the car and fully loaded. Follow reyes post. Better ride and normal wear. Now if youre gonna leave the car parked for any length of time then air to 60psi so the tyres don't flat spot

 

If you ran with 44psi in the UK, and had an accident, and your insurance company found out you could find they'd refuse to meet your claim as you had significantly departed from manufacturer's recommended pressures.

I don't know insurance companies are like in Aus, but here these days they will latch onto any reason they can find to refuse a claim.


In fact, even if you didn't have an accident but the Police stopped you for some reason, and tested the pressure of your tyres, you could end up with points on your license.

 

I run 40psi front and rear on my x350 running 245/40/19 front 275/35/19 rear used to run lower pressures but got sick of buckled rims
On my wife's jeep it runs 255/50/20 tyre's front and rear and I run 50 psi in it haven't buckled a rim in 2 year's

 

According to the mechanic who fitted my tyres (and he is a mechanic not just a tyre fitter)

he said that Jaguar recommend the tyre pressures for a soft ride and they have no interest

in tyre wear or petrol consumption.

Could be true I suppose.

 

I am with you on the pressure. Are you running Michelins? My first set of Pilot Sports wore out on the outside edges in 10k miles using the Jag recommended pressures. I, like you, noticed the max pressure is rated at 50 psi, so I tried running 45 psi on my second set. They run great and I am passing 20 k miles with no uneven treadware. The downside, as you noticed, is the stiffer ride.

 

Depends alon your average driving style. If you're always piloting, then go for higher pressures as edges will be very often sollicited. If your driving is quieter or a mix, I would go for recommended (on the high side, i.e. under load or speed) Jaguar pressures.

 

Oh my, he must hate Jaguar? Jaguar is actually doing the best they can in fuel mileage and tire wear.
Most of my driving is under 50 mph on country roads and I average about 40 mpg on Cooper's Zeon RS3-A on all 4 Paws. Oh, and I keep my 4 paws inflated to 32 psi.

 

After a bit of reflection I have dropped the tyre pressures to 40 psi so we will see how long the Kumho's last.

 

My Xj8 suffers the same camber-problem.
My rear left side hast much more camber compared to right side.
Toe seems to be in spec.
Is there a known defect, that causes camber to increase ?
( I bought my car 2nd hand, so maybe it's cause of an accident with bad repair ..)

 

Looks like there are shims on the rear.

Loads of info here and expert info from Brutal too!

https://www.jaguarforums.com/forum/x...-camber-48316/

 

At 50psi, you'd need to keep an eye on suspension components like bushes and rear wheel bearings. You may soon need to replace them because of the accelerated wear induced by higher than "normal" tyre pressure.

I kept my tyre pressure between 34 and 35psi for a long while to avoid rim damage caused by the many potholes on our roads. It didn't take long before I had to replace the rear bearings. The control arms also started leaking or became wobbly. I'm not suggesting that the bearings or control arms could have been affected by the tyre pressure, but it was too much of a coincidence that these problems emerged after maintaining tyre pressure at that level for about a year.

Perhaps if your roads are smoother than ours, 50psi isn't such a bad idea, but even still, you may as well get closer to recommended tyre pressure levels.

The best thing to do to keep tyre costs down, would be to check your wheel alignment settings every 6200miles or when you hit a serious bump or after driving on untarred road surfaces. It could save you lots of cash on tyres.

 

I am surprised to learn that accelerated wear of rear bearings already took place at 34-35 psi (50 psi I would understand). Are you sure that was the cause?
35 psi is not an uncommon recommendation for X350 tyres pressure, even more when driving under load and at speed.