The hinged side mount wood racks (aka dunnage racks) are a great place to store your 4×4 lumber, commonly used when hauling pipe. This 8 ft rack mounts under the deck and is welded to the main beam of the trailer. This option is very popular on purpose built hot shot trailers. The hinged door allows you to drop the door to store bulky items like tarps and toolboxes in the rack.