Abstract: A belt tensioner of the Zed type with a base member, a pivot-arm, a pivot-pin, a pulley attached to the pivot-arm, a torsional spring attached between the base member and pivot-arm, and wherein the base member has a "tube pan" shape with a cantilevered inner wall that supports the pivot-pin, a cantilevered outer wall, and a bottom wall interconnecting the inner and outer walls and oriented with the bottom wall juxtaposed the pivot-arm. Optionally, the spring is connected to a damping mechanism that generates a reaction force in generally the same direction as a belt force or hub load. In another embodiment, a second, damping spring generates a reaction force in generally the same direction as the belt force with a constant damping force.