Beside being able to install larger diameter tires, advantage or dis-advantage of moving front spring eyes rearward? Whats normal or maximum amount allowed? I have read some of 3/4 or one inch. I think it would move rear hangers to a bad angle?
If you're installing tall enough tires to warrant moving the rear axle backwards to gain tire clearance, you're probably going to be relocating the leaf springs as well anyway. Since relocating the leaf springs will require moving the rear hangers to the frame rail (some choose to install sliders), it's really not much more work to move them back to match how much you moved the rearend.
You just want to make sure the hanger is angled back slightly at ride height to allow enough suspension travel without hitting the frame at full squat, over bottoming out forward with the suspension at full droop.
An alternative is drilling new holes in the mounting pads on the axle tubes and shock mount plates to move the axle back a tad.
