I have 255/40 ZR19's on the front of my XJR and 275/40 R19's on the rear. The car was equipped this way when I purchased it. Seems to me that the tires should be the same size. Is that the case? Also, any suggestions on replacement tires. I live in Utah but don't plan on driving the car during the winter due to the salt they put on the roads.

 

Chances are your rims are staggered, meaning the rears are wider than the fronts. Makes it impossible to rotate. Three of my Jags came this way but I was never a fan and never noticed any handling improvement.

 

Check the tire label at drivers door opening. It will state how the car was originally equipped. My 05 XJR came with 255/40 R19s all around. Before changing the size of those rear tires I would verify that the rear wheels are the same as the front. Look at the part numbers on the wheels. It's a PITA. Perhaps a former owner switched them out. My guess is that somebody just put larger tires on your stock wheels.

BTW-- if those tires are Summer High Performance - you drive in Utah Winters at your own peril. Sounds like you already know that but I'm just saying. I recommend All season tires for Utah because you never know when you may have to take the car out. In my experience they will be quieter anyway.

Let us know what you discover and what you decide.

 

I have a 04 XJR and the tires are 255/40-19 all the way around. If you have stock rims they should be all the same size. The XK series has staggered rims. Do you have stock rims?

 

Sounds like they were swapped from an XK as they are staggered.