When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
You sure can down size to a 15" rim, as a matter of fact, the ranger FX4 level II's came with a 15" rim. 31" tires will fit nicely, I ran 32's on my 04 ranger 4x4 with no rubbing. I crank the torsion bars to level the truck, but the tires still fit before I did that.