Well some wd21's came with 31's anyway

. So you shouldn't have a problem after you raise the front the 2 inches. The rim i got For my full size spare makes my the tire stick out much farther than the legos and i didn't have any problem with rubbing when i came down the mountain with my spare on the passenger side, thats with flares and the underneath wind thing or whatever you want to call it... So i would immagine with a 31 1050 you should be fine.