Hey guys first post to the forums neway

I own a 99 1500 4x4 with a 3 in rough country suspenion lift under it and I am still using my stock rims. The truck looks great with a set of 285/75r16s under it but they rub on my upper control arm during hard turning. I could just suck it up and deal with it but i would prefer not too since i was also thinking about putting on a set of crager nomad steel rims. Easier to take care of and im not so concerned about a rock hitting them when im on the trail. So as to my actual question and or concern i dont want to change the backspacing or offset too much and put too much strain on my bearings. i think the backspace on the stock rims is 5in or something, so i was wondering if anyone had run into the same issue when running larger tires on thier ram. Should i get a different backspace or offset because i think changing either will get the effect im looking for and how much can i go before i start doing more damage than good. Also a friend of mine suggested switching to a 15in rim instead of the 16in rim on the grounds that it tends to be cheaper and easier to find the larger and more aggressive tires in a 15 instead of a 16 in rim. I did some checking on that and it seems im more likely going to run into even more problems attempting that cause the 15's will hit the calipers.
And thanks in advance for any advice and info!