I have a wheel and tire question.
 

I have a 72 Blazer with 3/4 ton axles. I'm considering running 15"x10" wheels with 33 12.5 15 tires.

The wheels I have in mind have 2.75" backspacing, and -70 offset. Am I going to have clearance issues?

Re: I have a wheel and tire question.
 

Depends on how much lift, what front axle you have, alot of 3/4 ton fronts will not clear a 15" rim because of the larger caliper. Thats why they came with 16-16.5" rims or larger.

Re: I have a wheel and tire question.
 

They are going to stick WAY out and depeding on lift may rub in the front. When you move the face of the rim out, it moves the tire way forward on turns and may/will rub on the fender depending on your lift.

With careful backspacing, you should be able to run 33's without a lift. I had 33 14.5 15 MT's on my Jimmy way back when on 8" rims which needed to be a little wider to keep tire from rubbing on wheelwell in the rear when you turned hard.

The 15" rims designed to fit the 8 lug axles came about so people could run big tires with safety beads back when 16.5" was the only option other than 15" for big tires. Now that there are so many options in 16"/17"/18" inch tires I wouldn't do it.

I have 16.5 x 9.75 inch Centerlines on my 8 lug axles and they have 4" backspacing. This is a much better choice for tucking the tires, especially only 33's. I "only" spent $1300 on wheels and tires and I bought 5 of each to have a matching pair. The Centerlines are chrome Bullets that were clearance at $150 each and I got 5 brand new Humvee bias tires for $550 delivered, but wish I spent some more up front to get radials and to get out of the 16.5 arena.

Re: I have a wheel and tire question.
 

With correct backspacing you can run 33's without a lift. That's the size tire I run with a stock lift (and stock axles). I have as much backspacing as possible (3 1/4") before the inner wheel lip contacts the outer tie rod.
I use an 8" rim however, as I didn't want the wheels sticking out too far.