The lower rocker arm in a motorcycle typically refers to a component in the suspension system. It plays a crucial role in the movement and function of the motorcycle's rear suspension.

The lower rocker arm connects the rear wheel or swingarm to the motorcycle's frame or chassis. Its primary function is to facilitate the movement of the rear wheel in response to bumps, uneven surfaces, and rider input. This component is essential for maintaining stability, handling, and comfort while riding.

The design and construction of the lower rocker arm vary depending on the motorcycle's make and model. It is often engineered to withstand the stresses and forces encountered during normal riding conditions, providing both durability and performance in the suspension system.

In summary, the lower rocker arm on a motorcycle is a critical part of its rear suspension, contributing significantly to the overall ride quality and handling characteristics of the bike.