Just fitted new tyres to the front of the XJ, just some reasonabley priced Nexen 8000s, they have plenty of grip and put the Pirellis on the back to shame, so to get some traction I fitted the fronts on the back and vice versa, great plenty of grip for quick getaways on wet cold roads but the handling was attrocious, the car weaved and wallowed on straights and dived into corners like something was broken, needless to say I have swapped them back and waiting for some new Nexens for the back. I can only guess it is caused by the way the Pirellis have worn on the back not suiting the front? I don't think it is caused by the new Nexens on the back, any one else experienced this on these Jags, seems they are very tyre sensitive.

 

What kind of Pirellis did you have on before? I'm looking to replace mine with some new Pirelli to replace the old Conti. Right now have 4 year old Contis that have the same symptoms you describe (wallow, wander, no grip)

 

The Pirellis are P6000 powergy, I think, but they have poor grip, really poor in the wet, makes car feel unsafe plus wheel spin when attempting to pull away at even modest throttle openings, the Nexens had loads more grip and half the price, don't do many miles so not worried if they wear out a bit quicker. I had contis on a Merc and had similar issues with grip and stability.

 

P6000 Powergys are not famous for their grip but still behave fairly unless they are really gone or you drive hard.
Those (to be changed now) that I still have on my XJ04 4.2 just bought this year have a DOT of 03 (ten years!) and grooves depths now limited to 3 mm on the rear and 4 mm on the front; they still allow driving safely in relax mode, of course no tough cornering or hard launches on the wet!

 

I have to say it handled ok with Pirellis all round, just suffered from poor grip in the wet, it was only when I swapped the new Nexens to the rear that handling issues made themselves apparant, put the Pirellis back on the back and it was a real pig wallowing and weaving, only concern really was is it the Pirellis on the fron or the Nexens on the back that cause the problem, i'd have to say it must be the worn Pirellis on the front, i can't see how the new Nexens would cause that sort of problem on the backs, I might be wrong, hopefully not as i've just ordered two new ones to replace the Pirellis, they should be here next week so i'll soon know.