why do my lugnuts loosen themselves??

[bdydrp97s10]

heres what i got..

73 up suspension in a 68..

the hubs on the 73 suspension stick out too far for the centercap to pop on my rims.. so i had a 7/8" wheel spacer made for both sides to push the wheels out enough to get the centercap on..

in doing that i had to get longer wheel studs, which i got from summit racing.. the studs are made for circle track cars..

and my lugnuts are threading on at least 3/8 of an inch on the studs and i torque them down as much as i feel safe doing without breaking the stud.

i noticed when i drive for 12-15 miles or so the nuts back themselve off to where the wheel is really loose and about to fall off.

another thing i noticed is that the rims themselves are extremely hot after driving that distance.. i know they might be a little warm from the brake rotor but thay just seem unusully hot to me..

anyidea why my lugnuts are backing themselves off over this short distance of travel??