Upper Control Arm

The upper control arm is a suspension component that connects the vehicle body or subframe to the steering knuckle, forming the upper link in a double-wishbone suspension design. Together with the lower control arm, it defines the geometry through which the wheel moves as the suspension compresses and extends, keeping the wheel hub aligned within its intended path of travel.

Each end of the arm has a distinct connection point. The inner end pivots on the vehicle body or subframe through one or two bushings, which absorb vibration and allow the arm to rotate as the suspension moves. The outer end connects to the steering knuckle through a ball joint, which permits both the up-and-down motion of the suspension and the side-to-side motion involved in steering.

During driving, the upper control arm carries lateral loads from cornering and braking, as well as vertical loads transmitted through the suspension. Its length and mounting angle affect camber change and other alignment angles as the suspension travels, which in turn affects tire contact and handling characteristics.