Wheels

Spacers

Spacers

>What is the maximum thickness a spacer can be without having to go with
>extended studs. All my buddy needs is about 1/2 to 3/4 inch to mount a set
>of 993s.

Automotion mentions a safe fit of nine turns of the lug nut. Since the studs and lug nuts are M 14 x 1.5 (shop manual page 40-02), nine turns is 9 x 1.5 mm = 13.5 mm (a little more than half an inch). Looking at it another way, adding a 1/4" spacer will shorten the available stud by 0.25 x 25.4 = 6.35 mm, or 6.35/1.5 = 4.23 turns of the thread. So, here's a quick way to find out: if you already have your new wheels mounted with no spacers, jack up a corner and unscrew just one lug nut; take it all the way off. Then start it carefully and thread it all the way back down, counting the turns as you go.. If you get at least 13 or 14 turns, you're fine for 1/4" shim spacers without changing studs (if you get 17-18 or more, you're OK for 1/2" shims; 21-22 will fit 3/4"). If you don't have enough stud left to be safe with the shims you need (presumably to get the inside of the rim and tire away from that pesky suspension stuff, but watch for the equally pesky fender lip on the outside), you'll either have to fit new studs ($$ for parts and significant labor) or use factory-type spacers with their own studs (easy but $$); check Performance and Automotion for listings of both options.
*Leonard Laub (leonard@visionthree.com); '87 928 S4 stick (black and ever so slightly enhanced)

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