I have a 1998 jaguar xj8 right now i have 18 inch rims on the car i want to go up 2 inches to 20's my question is will 20 inch rims with 245 35 20 tires fit on with no rub or problems at all. i would also like to know if i would need to change anything like the brakes bearings or anything else.

 

I believe the standard wheel and tire combination on an XJR is 255 40 18 and an an XJ8 225 60 16. For the XJR this combination would be about 10.0 to 10.1 inches wide with a tread width of about 9.0 to 9.1 inches and a diameter of about 26.0 to 26.1 inches. For the XJ8 standard wheel/tire combination the values would be approximately 8.9 inches wide with a tread width of 7.2 inches and a diameter of about 26.6 inces. The 245 35 20 size tire would be about 9.7 inches wide with a tread width of about 8.7 inches and a diameter of about 26.7 inches, so it ought to fit within the space available as the XJR and XJ8 should be nearly identical in wheel well size. I personally would go with a smaller diameter tire (235 35 20), since my XJ8's speedometer reads about 2 mph slower than actual at about 60 mph, indicating that the original tire diameter was a bit too big. A smaller diameter tire (26 inches) should result in a little quicker acceleration and more accrurate speedometer readings -- which would have come in handy the time i got stopped doing 81 when I thought I was doing 79 in a 70mph speed zone (Kansas). That 2 miles an hour would have made the difference between getting a ticket and not.