With some liberal trimming of the front plastic bumper caps and some hammering inside the fenders you can fit 33x12.5 TSLs (that measure out to 33.7"). So technically in theory you can run 34x10.5 LTBs that measure out to only 33.6". So yes you can run 31x10.5 with no problems, my own set of 31x10.5s have never rubbed even when flexing/stuffing the tires.

88 Raider(Red):160k-Reman'd 2.6-5spd-Weber-SW Hubs-34x9.5 TSL-OffRd Pkg-1"Tbar-2"BL-CB
88 Raider(Silver):No 2.6/Bad KM145 Parts/Project
88 Montero(Brown):No 2.6,4.88s Parts/Project

[b]4X4 STICKERS,SHIRTS,ETC:
4WD Stickers AT COST.[b]