This V-belt transmits power from the engine drive pulley to the main shaft of the harvesting machine's drive system. It sits in the primary drive loop, connecting the crankshaft output to the gearbox input that powers the header and threshing components. A worn or stretched belt slips under load, causing a drop in rotor speed and uneven crop flow through the machine. The belt is constructed by Gates to match the original cross-section and length, so it seats correctly in the pulley grooves without requiring tensioner adjustment beyond the standard range.