The twist axle assembly includes a pair of spaced apart trailing arms and a twist beam of which extends in a first direction between the trailing arms. The twist beam includes a pair of end portions and a middle portion. The twist beam further has a pair of side walls and at least one additional wall that extends between the side walls. The side walls in the middle portion are generally parallel with the side walls of the end portions. The twist beam is generally hour-glass shaped with the middle portion having a first width and the end portions have a greater second width. The twist beam also tapers from the first width of the middle portion to the second widths of the end portions for gradually increasing a torsional stiffness from the middle portion to the end portions.