How big of tires can put on my truck
 

2002 chevy 2500hd leveled buying 18x10in rims

depends how much you like your fenders! :tttt: all jokes aside i have seen guys run 35x12.5 with minor trimming of the valance and inner fenders on leveled chevy's. Then again i leveled my old truck and put on 33's and it rubber :dang:

33's are as big as you can go with no lift

You have to balance out performance and looks.