Abstract: Belt tensioning systems are provided for use with a belt transferring rotational force from a drive pulley to a driven pulley. One belt tensioning system includes a lever arm, an idler rotatably supported by the lever arm, a connecting link, a generally linear guide slot, and a weight coupled to the guide slot for generally linear movement along the guide slot. The lever arm has fixed and linking ends, and the fixed end is pivotably mounted on one side of the belt. The connecting link is pivotably coupled to the lever arm linking end and pivotably coupled to the weight. The belt is positioned between the fixed and linking ends, between the idler and the linking end, and between the idler and the guide slot. Downward movement of the weight causes the idler to increase tension in the belt. Chippers utilizing belt tensioning systems are also provided.