There are two functioning types of control arms — the supporting type and the guiding type: 

Supporting Type - supporting type control arms act as load-bearing supports, distributing vehicle body weight to the tire. 

Guiding Type -guiding type control arms distribute wheel forces, such as braking, acceleration, and other wheel actions, that require force transmission between the body and wheels of the vehicle. 

Design 

There are three basic types of control arms used in suspension systems: 

Press In - press in control arms are commonly used on more heavy-duty applications such as trucks and vans. This type of control arm consists of a forged arm with a receptacle for the ball joint. The ball joint is slightly larger than the hole inside the control arm, so when the ball joint is pressed into the control arm, a high amount of friction is generated that holds the ball joint tightly in place. Special tools are required to press the ball joint into the control arm to prevent damage to the ball joint, and the process requires safety precautions. Lizhong offers loaded control arms that include the ball joint and bushings to allow for easy installation and better alignment. 

Bolt In - bolt in control arms are usually manufactured with a stamped strut type arm body and are most commonly found on MacPherson type suspension. Repairing a bolt-in type control arm is frequently time consuming and can often cause alignment and fit issues with the replaced ball joints. Many Lizhong control arms are loaded with the ball joints and bushings to allow for easy installation and better alignment. 

Unitized - unitized control arms consist of one-piece control arms with the ball joint built into the arm housing. Unitized control arms are gaining popularity due to lower production costs, and they are commonly used in aluminum control arms. Because the unitized control arm is a complete unit, when a ball joint needs to be replaced, the entire control arm must be changed.

Metal design of internal components — Internal metal designs are widely used in the manufacture of Lizhong control arms. These designs incorporate highly durable upper and lower metal bearings that surround the ball joint stud and ball, and they include grease fittings to allow for grease and lubrication to be injected into the central area to prolong the life of the control arm. 

 Greaseable — Greaseable control arms enable the ball joint to be serviced, to flush out old grease and contaminants by injecting new grease during inspection and maintenance routines. 

Black oxide coating — The black oxide coating provides high resistance to variable corrosion factors such as road debris and adverse road and weather conditions, ensuring prolonged life of the Control Arm.