15 PSI with 285 and stock wheels
#11
i have done KC about 5 times before on my ATV, and i did it in my JK with no problems. had the tires at i think 16 PSI... idk. also did Hells Revenge, again, and Fins and Things in the JK instead of ATV.
#12
15psi should be fine, do it without issue on my stock wheel/tire size combo. If anything the 285's will hold the bead better.