Mechanical belt tensioning units represent a cost-optimized solution for automatically tensioned poly-V belt drives. The required belt preload force is usually generated by the torque of a torsion spring as well as the lever arm and the tension pulley. The damping package consists of a friction element (disk, ring and cone) that is preloaded by the torsion spring. As the lever arm moves, a relative motion in the damping package is generated, causing friction and, consequently, damping. The belt preload force (via the spring’s torque) and damping are adjusted to match the application. The materials used allow consistent damping values to be achieved via the temperature and frequency and with minimal run-in effects. Different designs permit optimum usage of the available design package.