My 2001 XKR currently is fitted with 18 inch rims
Rear 255/45Z18 and front tyre size of 245/45Z18

Is it possible to fit 19 inch rims (with new tyres) without any other modifications or will this mess up things like speedo and mileometer ?

Steve

 

You need to make sure that any replacement tyres are the same rolling circumference - tyre manufacturers used to publish the data in distributors' literature.These days you can probably google it. Another thing to watch is that the replacement rims have the same offset as the originals or else you can stress the bearings. If the rolling circumference is not the same the speedo will read incorrectly - anything over plus or minus 10% used to be a MOT failure (if it was picked up on, which I had happen to me on a XJS).

 

Here's one calculator for tire/rim size, there are several if you google
Online Wheel and Tyre Fitment Calculator. Offset, Tyre Stretch and Speedo Error | Will They Fit

Just keep your total circumference within 3% of stock to keep the systems working correctly.

I went the other way, stock was 245/40/19 front and 255/40/19 rear, I went to non-staggered 18's, 245/45/18 front and rear, no issues.

 

It is my very personal opinion honed over nearly 50 years of driving a extremely wide variety of vehicles, so worth every penny you are paying for it...


Anything beyond 18 inch diameter rims/tires, and sidewall heights under 45's for street use is pure affectation and a waste of money, not to mention unnecessarily adding harsh ride to boot.


Old guys like me think those oversized rims and slender sidewalls look foolish, too...and you surely don't want to look foolish to any old guys .

 

I'd recently moved from 18 to 19" wheels. I'd also increase wheel size from 8.0 -> 8.5" front / 9.0 -> 9.5" in rear. 255/40 front, 275/35 rear. Keep in mind you will require hubcentric fit (means the wheel fits to the hub, you may need adapters or spacers depending on your wheel brand. As far as any increase of harshness it can be managed by adjusting air pressure.

I won't go on there are many posts about wheels though I will say they aren't always clear on what they are saying

 

There are of course multiple paths for this, but by far the easiest is to somehow find happiness with another set of Jaguar XK8/XKR wheels. There were quite a few styles of wheels over the years, each one a perfect fit for our cars, no need to research offset, bolt pattern, hub centric parameters, etc. The only catch for your case would be the XKR brakes, which probably prevents you from going to the original "revolver" 17" wheels, but the rest is wide open.

The hard part is to locate a complete set in decent condition. In my experience, this is a low supply and low demand type of market, which makes prices normally quite reasonable (unless of course you are gunning for those rare sets from special editions), but it may take a while to find something nice. Also, the fact that these wheels typically do not fetch high prices sort of limit the incentive to refinish a peeling and curb-rashed set back to like-new condition. As usual, your mileage may vary, and you might get money back selling your current set as well, offsetting some of your new set.

Best of luck, keep us posted.