So I'm moving from 31x10.5 to 33x12.5 tires on stock suspension (with high clearance fenders). I test mounted a 33" on the factory 15x7 grizzly rim (5.5" backspace) to see what kind of backspace I will need when I get 15x8 steelies.
In the rear the 31" inside clearance is about 1", with 33" it's only 1/4".
In the front, 31" is 3" from tower and couple washers keep it off the LCA and sway bar. With 33" the tower is 2" but just barely clears LCA and hits sway bar.
Currently with both tires on factory rims, the edge of the tread is even with the edge of the flares. I know that 15x8 will also move the center of the tire out 1/2", meaning the inside sidewall will move out approximately 1/4". Seeing these pics, would you recommend 4" or 4.5" backspace to provide proper clearance without sticking the tires out too far? 4.5" will return the inner sidewall clearance to what the 31" had, and 4" will add another 1/2" more clearance than the 31"s but stick out even further outside.