A control arm (also known as an A-arm or wishbone) is a core component of a vehicle's suspension system. Its primary function is to connect the wheel steering knuckle to the vehicle's frame or subframe. It utilizes elastic connections like ball joints or bushings to transfer forces from the wheel to the body and ensures the wheel follows a predetermined path of movement.

Structure and Materials
Control arms are typically made from materials such as steel or aluminum alloys. Their common structural designs include A-arms, L-arms, and wishbones. They are connected via bolts and bushings to create pivot points.

Main Functions

• Force Transmission: Transmits lateral forces, braking forces, and other loads from the wheel to the vehicle's body. Conversely, it also transmits the engine's driving force from the body to the wheels.

• Motion Control: By using elastic connections, it guides the wheel along a specific trajectory and reduces the transmission of vibrations, thereby improving ride comfort.

• Stability Maintenance: Helps maintain the stability of the chassis structure, preventing issues like looseness, abnormal noises, and shaking during vehicle operation.

If the control arm's rubber bushings or ball joint become damaged, it can lead to problems such as chassis looseness, abnormal tire wear, and reduced handling stability.