so first off, i realize i hear it all the time, and i may have looked it up once, but what exactly is backspacing, and what is it used for (i.e. necessary to have 5" backspacing over 4.5" backspacing)? this will probably lead to another quesion (just so you know ) and with a 14bff, is a 16 inch rim a must? or can you clear the drums with a 15"? thanks.. oh, and another random one, does all 1/2 ton break lines/pressures work for 1 ton breaks (10 -14 bolts)?? thanks again..