I don't think the tires will fit a 4x2. I have an 06 screw lariat 4x2 with a 2.5" and the factory 20's, I've replaced them, but the wheel will fit no problem. The problem will be the 285/65/20, that's like 34.5" diameter, no way without trimming, and probabbly a substantial amount. You can fit 33x12.50's no problem on the factory rim, however the rim width is 8.5" and a 305/55/20 requires at least a 9" rim width. I'm running 20x9 MM 951's with 30mm offset(6" backspace) with 305/50/20 tires(32x12.50), by the looks of it, I don't think I would have had a problem with the 305/55/20(33x12.50).