Recently we replaced the OEM nuts due to previous abuse by tire changers. After much research on Google and other sources we determined the following info regarding the XK8, X-100 & X-150 series cars: 1997 thru 2005 use 1/2 X 20 SAE nuts (Mag type and taper to allow use with steel spare). The later cars, 2006-2016 use 12 x1.5mm Mag type and taper). The type we bought came from E-Bay vendor @ $24 for qty. 20. They required a bit of modification: removed .050 in length and came with 60 degree taper. The Shank diameter is accurate but just a bit too long. The taper had to be added back to the nut once it was cut. These were 13/16 nuts" vs 7/8" for the factory tool. This was addressed by purchasing a 1/2" drive, 13/16" spark plug socket to add to the tool kit.
The later cars, 2006-2015 show the 12 x 1.5mm lug and nut, but we would suggest one verify the length prior to just bolting them on. There was a considerable difference in the price of OEM vs these replacements and worth the extra effort to modify. Time to modify the nuts was 4 minutes per nut or close to 1 1/2 Hr. Work done on Bench Lathe. We've checked the torque reading several times and they were all still secure. This is our findings, but we do not guarantee you will experience our success. Use this info at own peril. (Rough Disclaimer :-)

 

I'm sure I've read posts by US members stating that solid stainless nuts from another vehicle marque are a direct replacement ........?

Graham

 

Mine has 19" wheels and the nuts are not tapered but have a flat "washer" on them so I can't help you sorry. I have read though that certain Japanese vehicles have nuts that will fit. I'm pretty sure a search on the XK8 forum for lug nuts or wheel nuts will turn up decent info.

 

Your are correct Barry, the Mag type nuts have a flat washer on the shank , but on cars with the donut steel spare, the nut have a bevel or taper at the end. The nuts are flat where the washer meets the wheel flange. I would think the cars with a spare matching the 4 on the car, would not require the taper. Apparently the taper or bevel is for the steel wheel spare use only. A Mag type would not center the wheel. The Mag type appears to center off the 5 shank as they pass through the wheel flange. The steel spare wheel has the tapers and centers off the nuts and taper. This is just my thoughts on how it functions.

 

My spare tire is held in place by thin steel rod with 6mm threads on one end. It's the space saver spare.

 

Not discussing the storage mounting of the spare. Should you have a tire emergency,(FLAT) and have to mount the spare tire in place of the regular wheels, the tapered lug nuts will allow you to drive the car to a repair shop or home at reasonable speed. Discovered this only by having ruined 1 of my new Conti Extreme Contact rear tires with only 1500 miles due to sudden loss of air. Had to use the Donut.

 

Did anyone ever find out what lug nuts fit?

 

This is what I got for my '97