I've done a fairly broad search, but have come up empty handed - so to confuse matters even more, I'd like to get some opinions in writing. Airing down - I noticed in videos and pics that my tires aren't bulging and conforming as much as others. I'm running 33 x 12.5 Goodyear MT/R's on 15" rims. How low can I *safely* air these tires down to without too much risk of blowing a bead. I've been staying around 18-20 PSI per a recommendation made by a cousin that's really more in to flinging mud and using the loud pedal - probably adding greater stress to the bead.