What size rims for street legal drag radials
 

We want to head back to the drag strip to see the difference last mods made but I had speradict traction issues last time and my Goodyears are too expensive to leave on the strip. 2007 XKR, so I thought I would get a set of dedicated Mickey Thompsons to run and started looking for another set of rims. I have the factory 19" should I go with that or would a smaller/larger rim have benefits. Regular brakes so plenty of room for smaller if it makes sense.
Me don't know, what say you?

I have no experience but out of curiosity I looked and found this.
Stock wheels will work with sticky tires, but if you want the most out of your car at the track, switching to a 15-inch-diameter wheel from the stock 17-inch wheel will help to maximize tire sidewall and absorb the suspension hit on the starting line.
so it makes sense that a smaller wheel of less weight and what they mention about absorbing the initial hit with the larger side wall. = less spin.

Smaller wheel so more sidewall wrap is a thing, but you still have to work around the caliper sizes. Thing is though, the Street Legal Drag Radials don't really have a whole lot of wrinkle-wall capability as that would preclude the Street Legal part.
For maximum usage, use the smallest wheel that fits the car (diameter-wise) and the largest tire that fits that wheel, unless you want to try a mathematically lower rear end ratio, just to see how it does.
I had a pair of Drag Radials on my Mustang GT, they lasted six runs before I had to replace them. Course I probably over-did the burnouts just a bit, but they did bite pretty good.

Ever consider Toyo R888r in the rear? They hook very well and are street legal, although not the best in the rain. You can find sizes to fit your stock wheels.

What CeeJay said.

Does Jag or anybody have a 17" rim that is same width that bolts up. Don't think a 16" would fit. What if I went with dedicated drag slicks that I change into at the track. This may be the route may make the most sense for best hook up.

That’s not going to clear the calipers and 18’s going to be tough as well

With standard brakes, I would expect 17" on rears and 18" on the fronts would go. The handbook suggests 18" wheels for winter tyres, so they must fit?

If you are going for a dedicated set, and the main difference are the rears, could you just swap the rears at the track and live with more standard fronts?

Is the rear tyre width critically important and should the wheel width be on the wider side of the range required by the chosen tyre? Stock wheels are usually nearer the minimum width for the tyres fitted by the manufacturer.

We have 1.5 inches between the caliper and factory 19's. So 18's for sure will work, in theory 17's should have a 1/4" of clearance. What year Jags came with 17's/18's and is the bolt pattern/width the same? I would expect the widths to be different. Aftermarket options? We will leave the 19's on the front. Searching on the internet suggests this rim swap has not been done much.

Look on Ebay for XK 18" rear wheels. Some were standard on the N.A. models and must fit. For example: https://www.ebay.com/itm/27487153608...kAAOSw~SBg86Ww

Beware though, some wheel designs have more rotor clearance than other designs of the same size. It's all due to the shape of the wheel and not tire size.

Specifically, barrel shape/size. Also be aware of offsets. Nearly all modern Jags have 5x108 bolt patterns and really, as neilr said, the rears are most important for drag and have smaller calipers/rotors so it may not be difficult to get the sidewall profile you need.

I run drag radials as my dailys, even in 19" size they will not spin at the track once you heat them up,
Doesnt rain a whole lot in central Texas. :-)
if you can find 18" wheels be even better but like I said even the 19s will dead hook. NO street tire will dead hook at the track with 500hp,
surface is not same as the street.