Abstract: An inverted U-shaped mounting bracket is bolted to the bottom of one pickup truck U-frame member at the rear of the truck and an inverted L-shaped mounting bracket is bolted to the bottom of the other truck U-frame member in laterally opposed position, pairs of forward and rear hanger arms are each pivoted at one end to said respective brackets and at their lower ends to the sides of a spare tire carrier rack to form a parallelogram arrangement for supporting a spare tire horizontally beneath the rear of the truck. A compact screw drive mechanism has its forward end respectively mounted to an extended outer wall of said inverted U-shaped mounting bracket and its rear end mounted to the same wall in the area of the pivot connections for the hanger arms to the U-shaped mounting bracket, and carries a screw rotatable about its axis and extending longitudinally along the U-shaped bracket which, in turn, carries a nut restrained from rotation but movable along the screw axis during screw rotation.