Abstract: First hydraulic drives (e.g. cylinders, pistons) and lift arms attached to dump truck side panels, preferably reinforced, move a trailing tag axle, and wheels supported by the tag axle, between operative and storage positions without bending the truck frame. A linkage assembly and second hydraulic drives (e.g. cylinders, pistons) coupled to the lift arms and the first hydraulic drives move the tag axle and the wheels between raised and lowered positions. In the operative positions of the lift arms and the tag axle, the wheels contact the ground and, because of the first hydraulic drive construction, move smoothly over road bumps and into road dips. In their storage position, the lift arms are disposed above and to the rear of the dump truck with the trailing tag axle and the wheels above the body but lowered to minimize their height above the truck.

Abstract: First hydraulic drives (e.g. cylinders, pistons) and lift arms attached to dump truck side panels, preferably reinforced, move a trailing tag axle, and wheels supported by the tag axle, between operative and storage positions without bending the truck frame. A linkage assembly and second hydraulic drives (e.g. cylinders, pistons) coupled to the lift arms and the first hydraulic drives move the tag axle and the wheels between raised and lowered positions. In the operative positions of the lift arms and the tag axle, the wheels contact the ground and, because of the first hydraulic drive construction, move smoothly over road bumps and into road dips. In their storage position, the lift arms are disposed above and to the rear of the dump truck with the trailing tag axle and the wheels above the body but lowered to minimize their height above the truck.