The Purpose of Control Arms, Bushings, & Ball Joints

The Purpose of Control Arms, Bushings, & Ball Joints

The Purpose of Control Arms, Bushings, & Ball Joints

Many drivers won't be familiar with the concepts of bushings, control arms, and ball joints. You may have never heard of them, but they play a crucial role in your car's or truck's suspension system by allowing the tires to rise and fall in a measured and safe manner. Your trip would be significantly diminished without them.

Control Arms

Front and rear suspensions on most vehicles use either one or two control arms per wheel. SUVs and trucks generally have a lower and upper control arm, while many front-wheel drive vehicles only use a lower control arm. A vehicle's frame is attached to the wheel hub and steering knuckle via a control arm.

The structure and the wheel are equipped with bushings and a ball joint, respectively, to allow for a degree of flex and controlled movement in response to road conditions and steering input. Control arms permit vertical wheel motion while limiting lateral motion.


An outer metal sleeve, a long-lasting rubber or polyurethane bushing, and an inner metal sleeve are the standard components of a control arm bushing. Bushings in the control arms are crucial for ride comfort and vehicle control. They reduce noise and vibration by easing the suspension's workload, and they make bumps easier to absorb. Bushings can bend and move in a wide range of motions without losing their rigidity or ability to recover their original form and position.


Ball Joints

Ball joints are the pivot point between the wheels and the suspension, allowing for slight movement in any direction. A single ball joint permits simultaneous rotation and movement in two orthogonal planes. Using two such joints and control arms, a vehicle's front end can be steered, and the ride can be controlled and comfortable using a spring and shock suspension.


Ball joints, bushings, and control arms are all crucial parts of the suspension and steering of a vehicle. When they wear out, it can compromise the vehicle's handling and comfort and even lead to the catastrophic separation of the control arm and knuckle. This is why it's essential to have your car inspected by a professional if you notice any problems with the suspension bushings, control arms, or ball joints.

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