On the 2005 Super V8 255 40 19 on 8.5 factory rims is what I have had for the last 80K+ miles. It was time for a third set of new tires so I also decided to change the rims to another Jaguar rim, Caravela, 8.5X19 front and 9.5X19 rear. Going with the tire sizes for the 2012 XK & XF I went with 245/40 19 & 275/35 19 rear which is about a half inch smaller in diameter than the originals and they look a lot smaller with a larger gap between the top of the tire and the wheel well. I have driven about 200 miles now and there is a difference, partially due to the old tires being worn out. It seems to be considerably firmer and more controlled but not harsher and better steering.

But now I see the 2012 XJ has 245/45 19 & 275/40 19 sized tires, about a half inch wider in diameter from the originals and an inch wider than what I have now.

My question is, what size should I have?