A belt tensioning system, tensioner and parts therefor and methods of making the same are provided, the system comprising a support unit, an endless transmission belt construction carried by the support unit and arranged to move in a certain path, an arm pivotally mounted to the support unit, a pulley rotatably carried by the arm and being in engagement with the belt construction, and an actuator carried by the support unit and having opposed ends, the actuator having a movable piston projecting out of one of the opposed ends thereof and being in engagement with the arm to pivot the arm in a direction to urge the pulley into the belt construction as the piston is extended outwardly from the one end of the actuator, the other of the opposed ends of the actuator being pivotally mounted to the support unit whereby the actuator pivots relative to the support unit as the piston thereof extends and retracts at the one end thereof.