The rear subframe on a motorcycle is a structural component that supports and connects the rear portion of the bike's frame to the main frame. It typically provides mounting points for the rear seat, rear suspension, and often the rear fender and tail light assembly. Made from materials such as steel or aluminum, the rear subframe is designed to withstand the stresses and loads experienced during riding while maintaining the bike's structural integrity. It plays a crucial role in the motorcycle's overall stability, handling, and comfort, and may be replaceable or adjustable for customization or repair purposes.