Wheels - moving up from 16 inch rims

I have a 1992 XJR-S with standard fitment 8J x 16 inch wheels, staggered fitting, so same rim size but front offset 19mm, rear offset 33mm. Jag spec tyres are 225/50 front and 245/55 rear, I’ve already gone up a plus size in width on the tyres, but there isn’t much choice for my next set of tyres if I stick with 16 inch rims. I already have stiff suspension upgrades, so anything above 18 inch would be just cosmetic, and only benefit the back specialist I would need to visit.

There are a number of different 17" and 18" wheel options from the later XK8s, or even Aston Martins, but what is going to fit, and give me the best tyre options? I’m leaning towards 17" rims but only see 33mm offset as an option. The 19mm offset on the front wheel is specific to the XJR-S, and also requires a 12mm spacer on the rack to limit the steering lock (as if the standard turning circle wasn’t barge like already). If I have the inside/outside offset correct in my head I would need a 14mm spacer. Probably still 8J on the front, but 8.5J or 9J on the rear?

Thanks for any ideas.

If you upgrade to 17" Revolver wheels, like I did, the spacers will be needed only if you want to put the caps:

http://www.jag-lovers.org/snaps/snap_view.php3?id=1428199053

My car is not XJRS but I do not believe yours requires the staggered setup (i.e., the XK8 wheel in standard form will clear the caliper and will not rub)

What is your objective? Appearance, performance, what?

Mostly choice of tyre. I checked a big UK supplier for the stock XJR-S sizes:

225/50 ZR16 - less than 40 available tyre types
245/55 ZR16 - zero availability

Moving up rim size:

225/45 ZR17 - about 250 types
245/50 ZR17 - 10 available

225/40 ZR18 - over 170
245/45 ZR18 - over 180

Last time I bought tyres I had to futz around with width and aspect ratio to get anything reasonable on a 16 inch rim.

I love the look of my lattice wheels, however yours do look cool, and I just happened to be given a spare set of revolvers with my XK8! Maybe in the near future I might swap them in. I wonder if someone makes a “low profile” grease cap. Hmmmmmm

This might help

http://bernardembden.com/xjs/rimtire/index.htm

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That’s really useful, thanks Bernard. I also found this generic calculator online https://www.wheel-size.com/calc/ that allows you to dynamically play around with the various wheel and tyre parameters.

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What did you go for? My R-S has 17" XJR alloys on it which look pretty good imo.

17" doesn’t look too bad, but I certainly wouldn’t go any bigger. I really think 16" is perhaps the optimum, appearance-wise. Just an opinion, of course, and you know what they say about opinions…

Are those wheels the same size all round, with a 33mm offset, and what size tyres do you have?

Yes they are, the fronts have a spacer on them. 235 45 17 on the front 255 45 17 on the rear *from memory though. She’s been at Emeralds in Norfolk for over a year…

17 inches it the maximum IMHO. I considered 18 “ when I upgraded years ago but believed they were too large for the fender openings. Looks are important, and the XJS fender openings were not designed for large tire/rims.