In case anyone was wondering, a 35-12.50-r17 will fit in the factory spare tire location on a rear coil spring ram 2500. It’s tight and don’t see how your gonna get anything bigger there. I had to deflate the tire and use a jack to force it up there. Once in place I could air up the tire and use gravity and my weight to yank it out. Idk if it’s worth it because there is only about one inch of difference in overall tire height.
Good to know, as many of us truck owners never give this much thought when upsizing a trucks OEM tires 1,2, or 3 sizes. I think we only start thinking ....Will it fit.....when the OEM under bed position is going to be reused.
Very few write ups are done on this subject. Thanks for posting this. On my classic(2003) 2500 HD, the original size was, and still might be the 245x75x16 tire. I upsized to the 285x75x16 with minimal issues. I just cranked the torsion bars slightly for full lock steering capability. Anything larger would have required a lift.
CAVEAT: This eliminates being able to use snow chains on the front axle, WITHOUT THAT LIFT.
As the original OP put forth, in his quest,........ my upgraded 285x75x16 tire Fit in the under bed position with no issues. This is a approximate 33" tire. It had room for a slightly larger size, what size? i don't know. But the rim riser elevates a tire and rim, right into the well, with no squeezing or finagling.
