alright! for those wondering (i think it was royal_t and someone), i got a 285/35 mounted up on my 18x13 kranze cerberus':
far from "extreme" but i had to fill them to 50 psi to get the bead to go all the way to the edge of the rim flange. mounted SUPER easy with the barrel style of the wheel. super pumped how they turned out.
tires are nitto nt555rII, r compound road race tires so sidewalls are pretty stiff