My Camaro has the long wheel studs on the back and I am constantly being asked what the purpose of them is, so I was wondering if someone could tell me, so I could tell them when they ask.

Dino

When running slicks NHRA rules state that the stud must extend a minimum of the diameter of the stud into the hex portion of the nut.

So if you have 1/2" studs they must extend atleast 1/2" from the surface of the rim.

I went and measured my lugs and I'm thinking they are 1/2" studs, but my studs stick out about 1 1/2" from the rim and just over 1/2" of stud sticks out past the lug. I'm using aluminum Centerlines. What is the reason for the rule, what exactly is the longer lug making safer.

Dino

Isn't it a 1/2" of threaded stud past the nut??

Supposedly the longer studs are needed to keep from pulling through the nut and also to keep from bending the studs when you have monstrous power and great big tires and rims.

I think that I have read where some of the turbo Buick guy's actually roll the big 9/16" studs and shear them off but may be wrong here??

Some guy's are stepping up to 5/8" studs and nuts b/c of this...

pdq67

The reason for the min diameter of the stud into the same depth of the hex portion of the lug nut is from history and from fastener engineering.

History has shown, in older pictures, slicks were ran on steel rims. This wasn't a problem, even today, a stock steel rim and stock lug nut have a few threads exposed from the end of the stud. As time went on, and alum & mag wheels came out, because of lighter weight and thicker hubs, some wheels came off due to broken studs/nuts due to too short of length and grip. So, NHRA adopted the min diameter of stud into hex portion.

From the engineering fastener stand point, the stud/bolt diameter into any nut/blind hole the same depth ensures the mininum amount of grip area for the bolt diameter being used. Having more thread sticking from the stud/nut combo doesn't mean its any stronger, its only as strong as the yield strength of fastener's minor thread diameter.

The reason of the stud being longer is from the manufacturer of the stud. They must make a stud to fit various thicknesses of wheel hubs, axle flanges, and lug nuts used on an infinite number of combo's.

I hope you understand.........just don't cut off the stud to the required length, it will decrease its strength if heated up.

And the stress on a stud in pull is equal to the area of the root metal area of the threads when both this and the minor diameter of the bolt is the same. you just have to add threads to get to them being equal.

I had to calculate this out when in school and if I remember right they are equal at about three threads vs minor bolt diameter!!! pdq67

The previuos owner may likely have had different wheels on before that needed a spacer which would require a much longer wheel stud. With a 1" spacer you would have about 1/2" showing beyond the nut right? That's my thoughts.
Lee

ARP says very emphatically on all their packages NOT to use wheel spacers with the longer studs. as already mentioned, some race aluminum rims have VERY thick hubs, and the long studs are necessary to get into the hex head part of the lug nut. and they just look cool sticking out like that. can't say they'd be fun if you got a flat on a rainy night, tho. that's a LONG ways to screw off a nut- and there are 5 per wheel.

And not to mention dirt in the threads b/c I have worried about this just by thinking of the longer part sticking out into the real dirty world!!! pdq67