I am looking into getting some new rims and have some questions. I know my stock rims have a backspace of 5.5". What is backspace and offset? If someone could please explain this. What would be the difference in these 2 wheels :

Size-----Offset-----Backspace----------Bolt Pattern
17x8.5----15---------5 3/8----------------6-135

17x8.5-----6----------5-------------------6-135

Thanks for the help guys,
Doug

 

Backspacing is the distance from the mounting surface of the wheel (where it bolts to the hub) to the outter edge of the wheel (back side). Offset is the distance from the center of the wheel to it's mounting surface. Backspacing is easier to understand because it doesn't change with the width of the wheel.
On the two wheels you are looking at, the second one will stick out 3/8 inch farther.