Dr. Diff 8 3/4 axles

Ok thanks for that info. I understand that it's about thread engagement, which was my concern if buying two sets of rims/wheels, one for street, one for race. I'd rather avoid the long 3" as I'm sure that would interfere with regular acorn style nuts. This means I'd avoid the 2 pc wheels as well. But I didn't know if I was missing something that I'd have to go 2" or 3" studs, no matter what rim I used for racing.