what backspacing for 15x7 with 33x10.5 tires

I have a 99 XJ with 3.5RE lift. I currently have 31x10.5 15 tires on stock rims. I run 26psi for everyday use, and 10-12psi when on the trail, and my tires wear very well. My tires dont have much life left, and I am now shopping around for new tires and wheels. I am going to get 33x10.5 15 tires, this I am sure of, I also want to stick with 15x7" wheels. My only problem is which backspacing to go with. I dont want the tires to stick out like crazy, but I want them to be far enough out to not rub on anything because of the extra 2" of height that the new tires will have. I am looking at 4.25 and 4.5" backspaced wheels, but have also heard to just go with 4" on a 7" wide wheel. I have already trimmed my fenders so that will not be a problem. So will 4.5" of backspacing work alright, or should I go with 4.25 or even 4" backspaced wheels? Thanks for any input.

That's a lot of backspacing on a 7" wheel. I run 3.5" of backspacing on my 15x7's with 33x10.50's. My tires still rub on my LCA's, and will also rub the inner fender liner at full bump/turn.

don't you want less backspacing? the backspacing is the distance from the mounting point on the rim to the edge of the wheel, so, a 15x7 rim with 4.5 backspacing means that 4.5 of that width is going into the wheel well. if you're trying to clear the suspension and steering components you want LESS backspacing, so that more of the wheel some out of the fender. so where crazyjim rubs on 3" of back spacing, you'd want maybe 2-2.5" of backspacing. which seems like and awful lot of tire sticking out of the fender. personally I like the look. but 7" wide, minus 2-2.5" leaves you with 5-4.5" off the other end. if you want a feel for how much it will stick out grab a ruler and go check.

i ran 15x7 on 34x10.50 LTBs. 4" BS. Worked perfect for me. No rubbing. Had my flares on too.

How much lift are you guys running?

I'm running 10.5 X 33s KOs, mounted on stock alloy rims and use 1-1/4" spacers, for a total backspacing of 4".
They sit inside the trimmed fenders (with raised flairs) and do not hit the LCAs. With 4" of lift and 5" of up-travel, the front inner fenders needed some massaging with a BFH.
Care was taken setting the bump stops to maximized up travel while prevent anything from bottoming.

i did the same.. massaged the inner fenders, and raised my fender flares. looked near stock. i didnt have any bumpstops tho, but never hit my fenders. i was on 4.5" lift. 10" wide is a BIG difference vs 12" wide.

Looks like it will be 15x7" with 4" of back spacing. Thanks for the input guys.