A bumper system including a bumper beam being cast from metal having a front panel and a back panel, extending between a first bumper beam end and a second bumper beam end. A plurality of reinforcing ribs integrally cast with the bumper beam extends between the front panel and the back panel defining a non-uniform cross-sectional profile along a portion of the bumper beam. The front panel includes a front center portion disposed between a pair of front side portions. The back panel includes a back center portion disposed between a pair of back side portions. The front center portion has a front center portion thickness greater than a back center portion thickness. Each of the front side portions has a front side portion thickness being less than a back side portion thickness of adjacent one of the back side portions. Method of manufacturing the bumper system is provided.