Well finally got some new feet for the Jag. Went up a size to 255's. Look much more beefy. Even the wife noticed it following me so it must look good, she NEVER notices that type of thing.
Question I have is what the hell tire pressure should I have in them. Tires say up to 51 lbs but that just aint ganna happen. Shop put 40 in them and it felt like I was riding on rocks.
The manual says diff pressure for this or that. What should I run in them for the summer.
I lowered them to about 36 in the fronts, 34 in the rears.
What say you?
They are Khumo (spelling?) Z or W rated tires, I forget.

 

I'm no authority but I recall 31 and 32 being recommended often. You may find your manual will state recommended pressure as well. My R also rode like a rock till I took it down to 32, Bettter after that. Keep an eye on the evenness of the wear for the indication of how much more or less that you need. We need pics Sir!

 

Tires can fit many different vehicles and the pressure stamped onto the tires is the MAX. they can safely hold. You should check the label on the underside of the center console lid. It's probably something like 31 front and 33 rear.

 

After you use the Jaguar recommended pressure keep a careful watch on tire wear. You can easily see center vs side wear due to the color of the rubber. Pump up or down as indicated. Side wear pump up, center wear let some air out. Mine wore best at 28 rear, 30 front and that also produced the best ride.

I just put new tires on the front today, boy what an improvement.

 

I thought CENTER wear was over inflation? Outer under inflation?

 

Color of ther rubber?

 

All I know is when I got the car the tires were fine, with in a year the inside was worn the most and I am fairly sure that I was running about 34-36 in them at the time.

 

My XKR with 20in wheels (285 rear and 255 front) calls for 32 front and 30 rear. That`s been wearing and riding well for me.....

 

I have been running 32 front and rear in my cars for years with good results.

 

Color of the rubber?

Scuffed vs rolling.

Inside wear is an alignment issue. I was trying to describe even wear both in and outside.

 

What do you mean color of the rubber?

 

Scuffed vs rolling wear.

 

similar here as many others, after 3 sets of tires to experiment and observe on, I've found 32 front, 29 rear works best for me.

 

If someone does not have a tire pyrometer, here's an inexpensive alternative:

-- warm up tires by driving normally

-- record starting tire pressures

-- draw 4 heavy lines across the face of each tire extending up the sidewalls a bit using chalk or a grease pencil

-- drive in a straight line a bit and look at the lines on the face to see where the tire is contacting the road

-- then, go for a real drive and look at the lines again, but now include looking at the parts extending up the sidewall

-- the parts extending up the sidewall will tell you how far the tire is rolling over during cornering

-- adjust tire pressures according to your personal preferences

-- repeat if desired

 

When I first test-drove it I found it a bit squirrely on slightly-rutted highway; turns out all tires were at 38. I have the 18 inch wheels, 245s front, 255s rear. I'm trying 32 front/34 rear now and that feels better. Interesting to see others running lower pressure in the rears - was that trial-and-error, informed guess? I feel some experiments coming on...

 

Set them for even tire wear. That will probably be the best comfort setting also.

Boy, do these new tires improve the ride. The Continental gum rubber tires that I got 20k miles out of were not good from new.

I bought Continental ProContact this time only because of the A/A/500 treadwear rating. My local tire guy thinks that the softer tires set a flat spot faster and therefore produce the out-of-balance feel. And I seldom drive enough miles in a trip to eliminate the flat spot.

Zero to 100 the new tires ride perfect. Wow! This car will go fast . . . er than anyone should.

 

Dropped from 34 to 32 to 29 based on tire wear only. Too high and the centers wear quicker, so now it is even across the tread.