Section 5:2 in the rulebook. "The thread engagement on all wheel studs to the lug nut must be equivalent to or greater than the diameter of the studs." I.E. With a 1/2" stud, the stud must be engaged in the hex portion of the nut at least 1/2".

Those thick Welds - or any other brand with the thick center - need long studs.

Drag radials will be more likely to break marginal stuff than a bias tire.