Drag racing/axle stud question

[Supersport350]

I almost have my Moser M9/Wilwood disc brake installation complete. I neglected to not I had went to 1/2x20x2" studs, and my lug nuts for my Weld Drag star wheels no longer work. I had asked Moser, and they stated that the 2" studs should be long enough when I bought the rear. Well, as my luck would have it, they are not. I went with the screw in style, so will be replacing them soon along with the lug nuts.

My question, I know I have to run open lug nuts for drag racing. Don't the threads have to protrude beyond the open lug nut? If so, by how much? I will still need a shank style to work with my weld wheels, but figured I'll need to upgrade to 3" and wanted to make sure I get what I'm going to need for the track so I don't have to buy yet another set later on this year.

As always, thanks in advance!

[Beagle]

the lug nuts have to engage for a length equal to their diameter is the way I understand it, ie, if your stud is 1/2 then the lug nut has to engage 1/2 inch of the stud.

I am not sure on the open part, I think that is for tech so they can see that the lug nut is not hanging on by two threads. If the stud sticks out of the nut, the odds are really good that the nut has engaged a length equal to the diameter.

[Loren]

^^ Exactly, with the clarification the stud has to extend beyond the wheel face by it's diameter and have the full body of the nut on it there and not just a diameter's worth into the machined-down shank in the wheel hole.

As an aside, note also that the closer the cut-down shank of the nut comes to the disc surface (without actual contact) the better as it reduces the length of the stud under shear (so you might want to get different nuts) but that's not in the rules as far as I know. Some guys just use an 11/16 stud, that fills the hole in a normal wheel, and you cap the end of it with a thick washer and special nut, I did that on the purple car.