Fatweed said "depends on what your going to haul in it? most of the typical bed boards are tongue and groove, and just screwed to the cross rails with a screw of that type that is self threading. Also, usually the boards are 1 inche...or 3/4...at least in grain beds...."
Sorry to disagree but most, as in nearly all, grainbodies built in the last 30 years have used 2" nominal lumber in a 6" nominal width. It is most always yellow pine and is shiplap, not T&G. One manufacturer (Omaha Std) did use laminated larch in a 1" dimension but hasn't been used in a longtime. Trailer flooring is generally 1-1/8" and is some form of imported mahogany subspecies. There are several. A lot of this is ualso used in CA platform bodies but they don't make grain bodies in CA or too many of them anywhere these days. Whatever is used it obviously needs to be the same thickness as the front half of the floor. And why use 2x4 when 2x6 or 2x8 would make it that much quicler to replace?
