Lugnuts with those caps. 19mm to remove. What size if the cap is off? I've got limited metric and 11/16 doesn't do it. I want to go buy one...

 

This happened to me on my XK150 several years ago. I believe I went down 1 in socket size. I apologize that I do not remember exactly the size that fit, but it can be done. I would suggest some penetrant so as to make removal easier in case you do not have a snug fit. Just make sure you clean the penetrant off with maybe carb cleaner and let it dry so that you get the right torque with the new wheel nut.
This is why I replace any capped nuts with solids.

 

I don't know the size for sure, but I am pretty sure that the ally material wrapping the caps is about 0.02" thick, or in metric almost 0.5mm. Allowing for both sides, I would give 18mm a try. This theory has worked for me on other vehicles.

Julesthejag.

 

There is absolutely nothing wrong with the OEM Jaguar lug nuts. They will last forever without any problems if you always use the correct size (19mm) deep socket and hand tools only, and use a torque wrench to tighten them to 92 ft.lbs.

Problems happen when tire jockeys who don't have metric sockets repeatedly use the closest size SAE socket that fits (usually 3/4") together with a power tool with excessive torque to remove and reinstall those lug nuts. That will eventually cause the outer shell of the OEM lug nut to deform and spin on the inner nut, thereby making it difficult to remove.

Don't blame the OEM lug nuts. Blame the lug who used the wrong tools.

See this thread for everything you need to know about Jaguar lug nuts:
https://www.jaguarforums.com/forum/x...-bolts-145997/

Stuart