Backspacing, another thread...

1st: Search has been done, but I need clarification since there is a lot of variation to the answers I have found.

Vehicle Details: 99 Sport, 4.5" of lift with RE Drop Brackets and Control Arms. Fenders trimmed(could trim a little more), and flares moved up. 33x12.50/15 Goodyear Duratracs on Eagle Alloy 15x8" wheels with 3.25" of backspacing. Just changed bumpstop from 3" poly RE, to 4" adjustable JKS. The change in bumpstop has limited my uptravel to 2".

Problem: Before changing the bumpstop I was slicing my tire on the fender and rubbing on the back of the wheelhouse(seam hammered flat) while turning and articulating. I would like to go back to 3 inches or less on the bumpstop and not rub.

Question: What backspacing should I run on a 15x8(with my lift combo) to reduce the wheel arc, while not rubbing on the control arm or other bits, and without adjusting the steering stops?

From my searching I have found people saying that anywhere from 4-4.5 should do the trick. I would like to get as much backspacing as possible, without rubbing and without adjusting the steering stops(this should help with bearing and ball joint life as well). So what is the magic #?

btt

To find out what the max you can run before rubbing on CAs is, turn the wheel and measure between the control arm and the tire following the line described by the tread surface. That is the maximum amount of backspacing you can remove before the tires will rub on the control arms.

Will that much actually solve your other problems? Good question. I just cut the fenders more when they rub, and hit the wheelhouse with a hammer a few more times when it rubs... or let the tire rub on it. Doesn't seem to significantly affect performance.

I'm not sure you'll find a sweet spot where you can get everything you're asking for. I prefer about 4.5" of backspacing, but I expect to run a washer under each steering stop bolt and I don't run 12.5" tires, 10.5-11.5" is a lot easier to work with