I have tried to absorb all the info here without asking this question but i am stumped. I understand to avoid wheel spacers i should maintain 4.5" of backspace. Just received a giant list of wheels both 17 and 18 wheels with correct bolt pattern. I believe in a 8" i need 0 bs. 8.5" -6 and 9" -12. Very few wheels with these requirements. What am i missing?

 

I'm guessing you're asking about Offset? My XDs are 17x9 and have a 4.5" BS with a -12 OS. The offset will determine how far the wheel will sit inside or outside the fender. 4.5BS with -12 offset sits about an inch past my fender.

 

All of those combo convert to approx. 4.5" of backspace.

 

I will use your wheel as an example. Half of 9" is 4.5". Subtract the negative 12mm offset = 4. Then add .5" for the lip of the wheel and it =4.5" of back space. The lip of the wheel is not added to wheel width thats why you add it back.

 

x2 on the BS, see the chart below.....

 

Carefull with 9" and -12. My old 9" and -15 with 35's hit control arms. And thing under a 0 offset is not approved fit on lifted jeeps. Now I'm at a +16 and great