90# is a little light from all the recommendations I've seen. I've seen anywhere from 110# to 135# for 5/8" studs. I use 110# personally. Hell, the 14mm (9/16") studs on my truck say use 135# I think on those. A typical 1/2" stud uses 90-95 usually.
Ive been given conflicting information by all the stud manufactures and the wheel manufactures. They each say the opposite.
Arp told me its the wheel manuf. and then I phone them and told me its the stud manuf.
5/8 studs have a larger diameter therefore should require a larger clamping force.
The other side to that coin is the studs are in shear and dont nessesarly require a heavy clamping load like a tension fastener ex. head/rod bolt.
Centerline told me to call back tommorow.
I recall the instructions on mine said to torque the stud in the axel at 140 Ft Lbs then tighten the lock nut to secure the stud in the axel. It didn't mention a torque rating for the wheel side but I use 90 Ft Lbs. That did mark my Pro Stars some But the solid centered Magnums seem fine. RM