When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Well, the 1988 lug nuts have shank diameter of .700"-.702", they fit tight in the wheels. Those Summit lags say shank diameter of .68"
I don't have the exact wheel hub centering stub diameter, but google says 73.8-74.X MM.
Something needs to center the wheels for high speed driving.
Conical lugs will do that of the lug studs are centered. A tight hub/wheel center interface will do that also.
Will .020" diff in lugnut shank diameter make difference on centering if the wheel hub is not almost a press fit onto the nub? I say probably not, though i would have to come up with something to fill the open centers of those summit lugs to be aesthetically pleasing.
AZ Doug
As I understand it, the Jaguar wheels are hub-centric, that is a machined conical male centre on the hub fits precisely into a machined conical female on the wheel itself. These are only about 1/4 inch deep on the rear hubs, but are deeper and more obvious on the fronts, but they do the wheel locating. The washer under the wheelnut is what holds the wheel to the hub, the washer being essential so the nut can clamp the wheel, without that the nuts would not clamp the wheel in place. The precise diameter of the nut tube (within limits, obviously) is not important in the XJS fitment, as long as it properly holds the washer to clamp the wheel. Rear hub with centric cone marked in blue
Front hub with centric cone marked in blue
I realise loads of cars have wheelnuts that are conical and that locate into conical depressions in the wheel itself. Jaguar XJS wheels are not located in this way.
The nuts come with a black rubber bung to close off the open end, by the way.
Last edited by Greg in France; May 11, 2026 at 01:18 AM.
I hate to question your knowledge, but I'm pretty certain that the wheel nuts on my 16" 5-spokes on my 94 car have conical (or at least "chamfered") ends which presumably locate into similarly-shaped recesses in the wheels. I've quickly googles XJS wheel nuts and most of the photos seem to indicate these chamfered / conical ends on the wheel nuts. Or maybe I'm misunderstanding your post?
Quick question: If that chamfer on the wheelnut doesn't fit into a corresponding chamfer on the wheel, wouldn't that mean that the contact patch of the wheelnut against a flat wheel recess at the end is very narrow?
The contact patch should be the flat washer, shown in the pic. as its steel washer to alloy wheel, the steel nut to steel washer contact patch is narrower.
Paul
AZDoug has answered you point to me, I think. If you remove a wheelnut and look carefully down the wheelnut hole, you will see the bottom of the hole is flat, not conical. You will also see that there is a circular gap round the wheel stud, and that the inner part of the wheelnut below the washer goes through this circular gap, thus allowing the washer to be done up against the flat end of the wheel hole.
I never mind my posts being questioned, by the way! The nice thing about this forum is that nobody is trying to 'outdo' anyone, and we are all used to being incorrect from time to time, the idea being to help us all keep these wonderful cars in top nick.
I measured these on my car and found that for the 5 spoke alloys as fitted to facelift cars the depth of the wheel centre where the studs go though is 13.5mm whereas the length of the corresponding wheel nut shank after the washer is 10mm. The standard extended wheel nut shank diameter is approx 17.9mm and the hole in the wheel is 18mm. The wheels are hub-centric as Greg says. I assumed the chamfers on the end of the wheel nuts was to facilitate locating the wheel nut when the wheel holes were not exactly centric with the studs.
