20x11x8

you might have to cut off a tab on the heel guards so the tires dont rub when you're in a corner
 
^^^ I had to do that. I think you could buy the stud spacers for the axle and not have to do that. I would do that and space out the front too so you have a wider stance.
 
my brother had 20" tires that were 11" wide and they rubbed the plastic heel guard

i have 20" and 11" wide but also extended swinger. if not for that i would be rubbing.

for 9" rims and tech4 tires it cost me $250 total for my rear tires. banshee hubs though