Will a 315/75 R16.. Fit on the back of my jk.. it has no body lift. no aftermarket bumper or tire carrier.. the rim its on has a 4.5" backspacing.. ???

 

no. get a daystar spacer kit to mount on factory components.

 

Yes, it will fit. I am running 35x12.5" tires (the same size as what you are asking about...34.6x12.4) on a wheel with 4.5" of backspacing and it fits fine. I had a spacer on my stock carrier when I had my 35's on my stock wheels, but with my new rims, no problem. You don't need a spacer for 4.5" wheels with that size tire. The tire just barely touches the bumper. The only thing I did was buy some longer rubber bump stops (from Quadratec) for the tailgate for the tire to push against since the stock ones are too short with a 4.5" backspaced rim.

Oh, I removed my rear brake light, so I am not sure about that part of it fitting.

 

If you're not running spacers for your wheels then you shouldn't need one for the spare.

 

Good info! I was wondering what that new rattling noise was back there, I just thought it was the soft top hardware. I gotta order those longer tire bumpers!

 

I also have 315/75R16's on 4.5" BS and it fits perfect. The bottom 1/8 inch of the brake light is covered but not enough to worry about. I also need the longer tire bumpers though.

 

I need the extended bumpers as well but can't find them on Quadratec. You mind sending a link? Thanks