hi ,im getting new rims and tires , but i need your help before i buy. im thinking about 18s for a celica. if i get 18s im worried that its so little tire that my rims are about a inch from the road , that if i run into bumps or pot holes that my rims will crack..... has anyone here had that problem before? if i hit those road bumps or pot holes will my rim crack or will i just get a flat. if its a flat its ok . because i can just replace my tires . its my rims that i dont want to have to buy another set if they crack . what are your expeirences with 18"s.?