Toothed discs for taper tensioning bushings - profile TB L number of teeth 20 L 075 for TB 1108 timing belts transfer the drive power via a form lock on the timing pulley. Unlike the V-belt drive, this is synchronous power transmission. It is distinguished between timing belt pulleys for finished bore and timing belt pulleys for taper tensioning bushings. They are available in metric and imperial divisions. Depending on the profile and disc diameter, this type of disc is available in steel (C45), grey cast iron (EN-GJL-200) or aluminium.