unless he will be running very low air in them tires he won't pop a bead off on the street, Ive been running 285's on my stock rims for 2 years now and have yet to pop a bead off the rim. I am also planning on stepping up to 305's shortly and will be running the same stock rims thats on it now.
maybe yall need to start actually looking stuff up before jumping to conclusions, according to this site ALL TERRAIN KO - BF GOODRICH @ NTW and BF Goodrich you can run a 315/70/17 on a 9in wide rim