This half wheel is a component of the gathering drum assembly on a combine harvester header. It mounts on the drum shaft and provides the surface that contacts the crop material, guiding it into the feeder house. The half wheel works in pairs to form a complete drum section. Wear on the contact surface reduces crop-gripping efficiency, leading to material bunching or uneven feeding. The manufacturer machines the part to match the original drum shaft fit and bolt pattern, so no additional shimming or modification is required during installation.