Officially Jaguar maximum size is 16″. Original size and recommended tires will give you the best ride and speedometer accuracy and of course give the correct rating for such a heavy fast car. Be careful what you fit as a lot of modern 17″/18″ alloys are not really designed for such cars as these. Remember they are very fast and much heavier than what one might think considering how agile they are.
Jaguar knew what they were doing all those years ago 🙂

I’ve done a bit of research on this as I wondered the same myself. Starting from the assumption that you want the overall diameter to be about the same as original to preserve speedo\odometer accuracy my summary is:
– 235 wide should (must?) fit as Jaguar specified this on later cars although I’ve never actually seen an xjs with these tyres on it as they are such an odd size in 15″.
– this width fits all 4 wheels the same offset
– I think 245 width can also fit but it would be very close
– wider tyres can be fitted but you need different wheel offsets front to rear (which is what TWR did to put 255s on the rear I believe)
– standard offset for Jaguar xjs wheels is 28.5mm
– wider tyres on the rear will hit the inner mudguard, on the front the inner steering\suspension somewhere (hence the need for different offsets). Rear wheels need to be moved inwards (larger numerical offset number) & the fronts outwards
– don’t forget that xjs’ also need a wheel with enough centre hub diameter hole to fit the front
– this is all theoretical, I run standard Jaguar 16″ wheels on my car!
Good luck.

Great information Alex, thank you for taking the time to share with us all:-)

I have seen a couple of XJS’s fitted with the 18″Aston Martin DB7 Turbine alloy wheels and Pirelli P Zero tyres.
As the DB7 is practically a mk2 version of XJS I gather these fit. Not my taste but there is currently a convertible on eBay with these fitted so you can see wheel fit.
I’d put a link to listing but not sure how – so check out Alpine green 1988 convertible – ‘reduced’ to £15,500 on eBay – 5days until ends.
Aston wheels are often available as owners update the early DB7 wheels for later versions – cost even more than Jag ones when new..

Robin

Trouble with EBay links are they get archived by eBay and disappear

Here is a couple of photos of the car Robin mentioned

I had these fitted to my grey can (still got a set of spacers somewhere from it)

Laurence

What ultimately matters is the size of tyres you fit. On 18 x 8″ rims you could fit 235/45 tyres and they will clear but if you put 255s on I’m guessing you might have problems. Is it legal to use spacers in the UK? You can’t in Victoria.