Does the width of a wheel have anything to do with the backspacing? I mean if you start with a wheel that is 17x7.5 and 6" backspacing then move to 17x8 with 6" of backspacing, do you get .5" more room for tire width? Or is it .25" more room? I read the faqs but still not sure.

 

Both wheels are 6" of backspacing so both of their hubs are 6" from the inside of the rim. The extra rim in this case is on the outside. Here's a picture that might help

 

6" of BS is 6" of backspacing this does not change with wheel width. BS is the portion of the rim that mounts to the lugs and brake rotor to the backside of the rim. like mjolnir's diagram.

You need to either get wheel spacers or a different set of smaller BS'ed rims. A lower BS'ing rim will allow you to fit wider tires like 12.5 to 13.5 wide tires. The lower the BS the further the tire/rim is away from the suspension components. Normally people will get a rim that is somewhere in the neighbourhood of 4.5" BS on our JK's to fit a 12.50 tire to avoid rubbing.

 

So if I have a wheel that is 17x8 and 5.50" BS, do you think I could run a tire thats 11.3" wide and 33.75" tall (via the factory website) without rubbing?

 

Im running 285/70/17 (33x11.5) MT on stock rim (6.25''BS) with no wheel spacer and I have no major rubbing issues, at full turn they rub just a little on the sway bar, you can get rid of this problem either by buying wheelspacer or by ajusting turning radius (5min mod).

 

I should work with that narrow of a tire. If you are considering a wider tire (12.50) in the future I would really consider looking at a rim in the range of 4.5BS.