This V-belt transmits drive from the chopper input pulley to the rotor assembly inside the straw chopper. It sits on the two-groove pulley system that powers the chopper drum, which processes material leaving the threshing section. A worn or slipping belt reduces chopping speed, leading to uneven straw length and increased load on the drive bearings. The belt is constructed by Gates to match the original cross-section and length, preserving the tension range that the tensioner arm was designed to maintain. On replacement, verify the belt rides flush in both pulley grooves and adjust the tensioner to the specified deflection.