i had a set of 35x12.5 on 15x12. I wouldn't run it IMO it looked retarded...i never got to air them down my POS Ford blew a tranny reversing out of the tire shop <img src="/forums/images/graemlins/rolleyes.gif" alt="" />
i think you would pop a bead fairly easy especially airing down for sand

what wheels do you have now? 15x7 minimum for 12.5, to stay safe i'd say 15x10 max


'88 Raider, 33" Maxxis, 2" body lift, 10K winch