Why does the build not include adding springs to the frame?

A trailer can be built with or without springs. Using a square tube axle makes it easier to weld the axle directly to the frame. But an axle without springs produces a harsher ride. Springs can be added to provide a softer ride for your cargo, but the center line of the axle should still remain in about the same location specified in the article. The spring mounts should be located in order to place the axle in the proper position.The fixed end of the spring should be toward the front of the trailer, and the part that is allowed to move should be toward the rear of the trailer.