6. While wall thickness is important and does add strength to an axlehousing, bumping up the overall diameter of the tube adds even more strength. On the left is a 31⁄8-inch-diameter, 5⁄16-inch-wall tube that would typically be used in a rear semi-floating axle. The middle is a 31⁄2-inch-diameter, 1⁄2-inch-wall tube that would typically be used for a front or a rear full-float axle. To the right is the whopping 4-inch-diameter, 1⁄4-inch-wall tube that went into our ProRock 80 rear.