Friends:

I'm forced by safety considerations to replace the stock 1/2" - 20 RH wheel studs (front and rear) on a newly-purchased 1977 XJ12 L , with longer versions of the same. After purchase, I discovered that only about a +/- 9 mm length of the tapered lugnut bore thread was attached to the stud . . . ouch! . . . and a bit scary (not to mention steering wheel vibration at +80 mph). The added thickness of a Borbet mag rim plate accounts for the too-short-studs.

I've just now ordered a set of Mr Gasket studs p/n 4311 (Summit Racing p/n MRG-4311) which are 2.875 length overall.

This new overall stud length will pass all the way through the thick Borbet wheel plate, and can be cut to an appropriate length later.

But . . . I have not yet removed the old, short studs from the car and so am only guess'in as to the knurl diameter. It appears from my indirect researches of aftermarket supplys that the most likely knurl diameter is 0.665". Can any reader out there confirm the required knurl diameter for my wheels?

What is the required knurl diameter for the stock OEM wheel studs on the 1977 Jaguar XJ12 L front/rear????

Hows about a little help for a humble new member, OK???

Cheers,

Bob H
Nelson, BC

 

hello!
click the below link to see if it helps you get the information you seek:

L.A. Wheel and Tire

 

Thanks Jose but this link while valuable, doesnt have any info about knurl diameter.

 

I think you're going to have to find a wheel stud from somewhere and measure it up. These parts are probably the same right up to when the Series 3 XJs stopped production in 1986.

Doug will probably know.

 

they manufacture lugnuts for Jaguar so you might contact them for precise measurememnts.

 

wheel studs for the XJ 12 L 1977 were 1/2" - 20 (tpi) press ins . . . that makes them unique..The other Series 2 types for '77 (and later thru to Series 3) are/were screw ins, M12 - 1.25s . . .. As to your advice re find another stud from another XJ 12: yes, I'm coming to the same conclusion. By the way, who's "Doug"? Can you link me to him?