This video shows the differences between the older design single bolt to hub and the three bolt to hub design. The axles are both for a Bobcat 873 , single bolt design from the late 1990's. If you need a three bolt axle or hub of the newer three bolt style in the greater Cleveland area, I have one. I beleive the tapered section of the shaft is connected to the spline shaft using inertia friction welding and was marginal for the load so the manufacture enlarged the part to make it more robust.