This variable-speed belt transmits power from the engine to the threshing drum, allowing the drum speed to be adjusted to match crop conditions. It runs between the variable-pulley set on the engine output and the driven pulley on the threshing shaft. A worn belt slips under load, causing inconsistent threshing speed and reduced separation efficiency. The belt’s multi-rib profile matches the original pulley groove geometry, ensuring proper tension and grip without requiring pulley replacement. On installation, check the belt tension and adjust the variable-pulley position to the specified range.