Jul. 21, 2025
Control arms are structural suspension system components that connect the vehicle’s chassis with the wheels. The control arm connects to the chassis with bolts that run through bushings. This connection acts as a hinge allowing the control arm to move vertically or horizontally depending on the orientation of the bushing. This hinged movement is important as it allows the wheels to move independently of the chassis which improves ride comfort and handling performance.
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The other end of the control arm is attached to the wheel hub with either bolts or ball joints depending on the suspension type and location of the control arm. The ball joints help with suspension articulation to maintain wheel contact with the ground as the vehicle goes over road imperfections and in the case of the front wheels, these ball joints allow the spindle to rotate freely.
The number of control arms and the type can vary based on the suspension type and location of the arm. Independent suspension systems utilize one or more control arms according to the design. Most vehicles have front control arms but only a few have rear ones. The most common types of front suspension include Double Wishbone and Macpherson Strut. Control arms can be either an ‘A’ or ‘L’ shape or a simple shaft.
The main function of control arms is to isolate the wheel movement from the chassis which does two things – Firstly it helps dampen vibrations from the wheels, providing smooth and plush ride quality, and secondly, it maintains constant wheel contact with the ground for better steering and control over the vehicle. This is the reason why broken control arms can compromise vehicles’ safety and put the driver and passengers at serious risk.
Control arms can come in many different shapes and sizes, but most commonly, they are shaped like a capital letter “A”. The two lower parts of the “A” are attached to the frame via control arm bushings, which are rubber pivot-points. The top of the “A” is attached to the steering knuckle by way of a ball joint.
The most common types of control arm suspensions are:
In a control arm type suspension, the control arm is a separate component from the shock absorber. The control arm is connected to the frame of the car and the steering knuckle by ball joints. The shock absorber is mounted separately.
In a strut type suspension, the strut becomes the upper control arm and is sometimes connected directly to the spindle or the lower control arm. Strut type designs have a lower control arm but no upper control arm.
The lower control arm is a component of the suspension system in a car that helps maintain contact between the wheels and the road surface. It is a link that connects the frame of the car to the wheel hub assembly or steering knuckle. The control arm moves up and down with the spring when a car hits a bump or other road irregularity, allowing the tires to maintain contact with the road and, thus, control. The two lower parts of the “A” are attached to the frame via control arm bushings, which are rubber pivot-points. The top of the “A” is attached to the steering knuckle by way of a ball joint. When a control arm fails, multiple things can happen. Most failures occur from the ball joint failing. Complete ball joint failure can cause a steering knuckle disconnection and loss of control of the vehicle. Control arm bushings can also wear and fail, creating clunking, wandering steering, and loss of control.
Moog Control Arm Assembly
Mevotech Control Arm Assembly
Dorman Control Arm Assembly
Delphi Control Arm Assembly
The suspension system of almost all vehicles is different from one another and this difference may even exist between different models of a particular make or even versions of the same car. This makes it necessary to choose control arms specific to your vehicle’s make, model, and year of manufacture. Normally you can find it very difficult to find exact matching parts for your car in the aftermarket but PartsAvatar makes it easy for you. Select your car’s exact model, make and year to get products that are direct OE replacements. This removes the guesswork when buying new parts.
As mentioned earlier, control arms are mainly built with three materials – iron, aluminium and steel. Aluminium control arms are lighter than other types which translate to reduced unsprung mass and lighter weight on the vehicle. Such arms can absorb noise and vibrations better due to the density of the material. Another advantage is their corrosion resistance making which allows them to be used in varied weather conditions. Therefore aluminium is ideal for performance and luxury vehicles as they provide enhanced comfort and handling properties or in places where the weather is mostly wet.
Steel control arms are more affordable than aluminium and generally have a long service life unless exposed to constant wet conditions. These types of control arms are sufficient for most compact cars and sedans that do not face harsh driving conditions.
Cast and forged iron control arms are sturdier than steel and can withstand heavier loads which is necessary for heavy-duty applications like trucks and pickups. They can even be lighter than steel arms for reduced unsprung weight.
One of the most common reasons for control arm failure is corrosion. Due to their location, the control arms are always exposed to the road and weather conditions making them vulnerable to rust which can significantly reduce their service life and will require more frequent replacements. To combat this, many manufacturers apply protective coatings on steel and iron control arms to prevent corrosion and extend component life. When buying steel or iron control arms it is necessary to look for resistance coatings that ensure the components will last a long time and provide a healthy service life. Such treatments are usually showcased by the manufacturer so look for the information before buying new control arms.
Replacement OE components offer the same advantages as the factory-equipped parts and nothing more. This means you will not receive any additional benefits. These will also cost quite a bit more than aftermarket parts. Whereas aftermarket components are generally cheaper and come at a reasonable price while providing many benefits over standard control arms. Aftermarket components match the fit and performance of the OE parts and some even exceed that. Hence making them a bargain over OE counterparts.
Control arms are available as a single unit or complete control arm kits. While a full kit is recommended, if replacing just a damaged section then a single control arm is more feasible. Usually, it is best to replace both fronts – right and left, or both rear control arms together including the upper and lower arms if your vehicle has both.
Opting for a full control arm kit will ensure you don’t have to worry about replacement any time soon. Since the control arm replacement can be expensive, it is generally more economical in the long run to go for a complete replacement to minimize labor costs. Full kits also come with all the required fasteners and parts, which reduces cost and saves time during installation.
Different brands offer different advantages and benefits. These features need to be considered when buying new control arms. Some aim at making the components durable, while others offer easy installation procedures. To get control arms best suited for your needs, consider the technologies used to manufacture them. Corrosion treatments and powder coatings on control arms resist corrosion and last for a long time. Another thing to consider is the warranty offered. If a company offers a lengthy warranty for their control arms, it can mean that they are confident about its quality. So the features mentioned along with the various brands can help you match the one best suited to your needs. The brands mentioned here are a few of the best manufacturers in the market producing OE equivalent components at a much more reasonable price which is why we recommended those brands.
The control arm design and construction can vary depending on a few factors such as suspension and vehicle type and the location of the arms. The types of control arms are as follows:
There are adjustable and non-adjustable control arms. Adjustable ones can alter the alignment of the wheels. Such control arms have threaded sleeves that travel inwards or outwards to push or pull the wheel which changes the camber angle.
Since control arms are structural components they need to be made of robust materials that can withstand heavy loads, stresses, and pressures. This means the material choice needs to meet high standards as well as the manufacturing processes to ensure safe, reliable, and long-lasting service life. The materials used for control arms include steel, aluminum, and iron. Steel control arms are the most widely used type due to their strong construction and inexpensive manufacturing. Steel control arms are often used as OE by manufacturers as they are cheaper to mass-produce and have high strength characteristics. The drawbacks to steel control arms are their heavier weight and susceptibility to rust. Cast and forged iron arms are similar to steel counterparts in strength but weigh less and can withstand much heavier loads and varied weather conditions making them ideal for trucks and heavy-duty vehicles. However, these are also susceptible to rust.
Aluminum control arms have many advantages over steel and iron alternatives, most importantly they are not prone to corrosion. They are also much lighter than steel which is favorable if you want better driving and handling dynamics from your vehicle. Suspension components contribute to the un-sprung mass so the lighter the components the better the vehicle will tackle a turn. A reduction in overall vehicle weight is also an added advantage. Well-made aluminum control arms can match and even exceed the strength of steel arms. The only drawback is that aluminum does not flex under stress, unlike steel, which can result in cracking or breaking under heavy-load conditions or upon impact.
Control arms can be classified as supporting and guiding types based on their functionality. Supporting type control arms are load-bearing and support the weight of the vehicle. Whereas guiding control arms help distribute various forces like braking and acceleration to the wheels evenly. They are not loaded but provide structural rigidity to the suspension and wheel assembly.
The control arm design mainly varies based on how the ball joint is attached to the arm. There are three variations – bolt-on, press-in, and unitized control arms. Bolt-on type control arms have an indentation and holes where the ball joint bolts onto the control arm. This allows the ball joints to be replaced independently of the control arm and vice-versa. These are generally made of stamped steel. Similarly, press-in type arms have ball joints that are integrated into the control arm but without the use of bolts. Instead, the ball joints are pressed into a receptacle in the control arm that accepts the joint. Such control arms are made with forged arms for sturdier working and so are commonly used on heavy-duty vehicles.
Unitized control arm assembly incorporates ball joints into the arm with the ball joint built into it. This means the ball joint or control arm alone cannot be replaced and the control arm assembly needs to be replaced entirely. Unitized control arms are becoming increasingly popular due to lower production costs and are commonly made with aluminum.
Control arms are a critical safety component-to ride right, to handle right, and to ensure safety and dependability they need to be engineered and built right. Moog makes thousands of control arms for the broadest range of applications. And while no two applications are the same, every Moog control arm is engineered and manufactured with the same goal in mind-to ensure durability, reliability, and performance.
Moog Premium Control Arm Part Numbers: CK, CK, CK, CK, CK, and more.
Premium Control Arms Features:
Moog R-Series Control Arm Part Numbers: RK, RK, RK, RK, RK, and more.
Moog R-Series Control Arm Features:
For more information and a detailed product line, visit Moog Control Arm Section.
Mevotech gives technicians the edge, by innovating every control arm component. On average, installing their control arms takes 30% less time because the ball joints and bushings are pre-installed. Mevotech engineers focus on making the components easier to install and built to provide a long-lasting service life. Employing rigorous durability testing, they validate every new design to ensure you get the performance you can trust.
Mevotech Control Arm Part Numbers: CMK, CMK, CMS, CMS, CMK, and more.
Features:
For more information and a detailed product line, visit Mevotech Control Arm Section.
Delphi Technologies Chassis products are manufactured to meet the exact same tensile strength, flexibility, and longevity as the original equipment. They test their products alongside the OE part for 250,000 cycles to check braking force, cornering force, and suspension travel movement, so you can be certain the part will perform like the OE.
Delphi Control Arm Part Number: TC, TC, TC, TC, TC, and more.
Goto Zegao Machinery to know more.
Features:
For more information and a detailed product line, visit Delphi Control Arm Section.
TOR offers a full range of heavy-duty steering and suspension car parts, built for optimal fit and extended service life. Each component is tested throughout the manufacturing process to ensure exceptional performance and reliability.
Transit Warehouse Control Arm Part Numbers: TOR-CK, 72-CK, TOR-CK, 72-CK, TOR-CK, and more.
Features:
For more information and a detailed product line, visit Transit Warehouse Control Arm Section.
Dorman suspension control arm and ball joint assemblies are a direct replacement for the original equipment on wide-ranging vehicle applications. An industry-leading evaluation process ensures directional stability, a smooth ride, and favorable dynamics.
Dorman Control Arm Part Numbers: 520-494, 520-493, 520-866, 524-113, 521-108, 526-289, 521-637, 524-102, 520-283, 520-284, 522-467, and more.
Features:
For more information and a detailed product line, visit Dorman Control Arm Section.
No matter what material the control arm is built with or how well it is built, it is vulnerable to wear and tear especially because it undergoes immense stresses and forces regularly which can eventually cause the component to fail. The signs of control arm wear become more obvious as it deteriorates and so it is important to look out for these signs to scope out the issue beforehand and replace it to minimize damage.
The most common failure point of control arms is the bushings. Since these are used to minimize vibrations, worn control arm bushings can induce vibrations in the wheel that can even travel all the way to the steering wheel. Failing ball joints can also cause vibrations. An uncomfortable rive is an early sign of something going wrong with the suspension components.
Worn bushings and ball joints upset the alignment of the wheels which can cause the vehicle to steer from left to right involuntarily. This will cause the driver to lose control over the vehicle and can be seriously dangerous when traveling at high speeds.
When the bushings wear out, the metal components directly contact each other which gives rise to clunking and knocking noises. These sounds are more prominent as you accelerate and brake. Ball joints show a similar symptom when they fail as the play within the joint increases, the control arm becomes loose and noises increase. These sounds are faint at first but if ignored, the noise intensifies and so does the problem.
There are several reasons for uneven tire wear which include bad control arms. Since control arms are integral suspension components, wear and tear of the components causes the wheel alignment to be changed which modifies the wheel contact patch and results in uneven tire wear. The inner or outer tire shoulders may wear more than the other end indicating uneven tire wear. Inspect your vehicle immediately to mitigate the problem and find a solution.
If your car has a broken control arm, it is not safe to drive. If you must move the car, it is best to have it towed to a repair shop. Driving with a broken control arm can cause a steering knuckle disconnection and loss of control of the vehicle. If you’re unsure about how to proceed, it’s best to have your control arm replaced by a professional. You may find it simple to replace a front lower control arm on a vehicle with a MacPherson strut suspension. But if you’ve got a torsion bar suspension, you’ll need a lot of mechanical knowledge in order to complete this job.
A car's control arms play a significant role in how it rides and handles. If you've been told you need to replace the control arms on your vehicle, you're aware this is one of the more expensive suspension repairs, but it's an important one. Control arms play a key role in vehicle safety. In addition, control arms that aren't up to par may result in increased wear on your tires and other parts of your vehicle.
Today, let's take a closer look at control arms and the common (or uncommon) questions you may have about these suspension system parts.
1. What Do Control Arms Do?
Front Control Arms: The front control arms connect the front wheels to the car chassis. They're responsible for controlling the up-and-down movement of the wheels. When you hit a bump or a pothole, the front control arms help absorb the shock, creating a smoother ride while keeping your steering in check.
Rear Control Arms: The rear control arms perform the same function as the front control arms, except they are located in the back and connect the rear wheels to the car's frame. Rear control arms keep your rear wheels steady, whether you're driving on a straight road or taking a turn. In addition, they help your car's stability—especially during sudden stops or sharp turns.
Both the front and rear control arms keep the wheels in line, play a part in ride comfort, and help you steer.
2. How Many Control Arms Does My Car Have?
Modern vehicles tend to have between two to four control arms, depending on the make and model.
3. What are Control Arms Made of?
Control arms are usually made of aluminum or steel.
4. How are Control Arms Connected to My Car?
The control arms are attached to the car via bushings that allow them to move up and down.
5. When Do I Need to Replace My Car's Control Arms?
Often, control arms are replaced when the bushings or ball joints are changed.
6. Why Should I Replace the Control Arms with the Bushings?
Control arm bushings tend to be made of rubber because it is a soft material that's good at reducing road noise and vibrations. However, their rubber construction means the bushings are susceptible to dry rot, tears, and cracks. Bad control arm bushings make noise and have visible wear or damage that indicates it's time to replace them. You may also notice abnormal tire wear or an off-center steering wheel.
Why do motorists replace the control arms at the same time as the bushings? It's because it isn't that much more expensive to replace the entire assembly. Another reason is that it's actually easier to replace the entire assembly, saving you on labor. It makes sense to pay a little more now to have new control arms, bushings, and ball joints vs paying again if another part reaches failure.
7. Can I Replace the Ball Joints and not the Control Arm?
On some vehicles, the ball joints cannot be replaced separately from the control arms. On vehicles where it is possible, the ball joints (whether they are press-in or bolt-in ball joints), require special tools for replacement. This typically involves extra steps vs replacing the entire assembly. A new assembly would include a new control arm, new ball joints, and new bushings. Similar to bushing replacement, it makes sense to do everything at one time vs paying again in the future due to worn bushings or control arms.
8. Should I Replace the Control Arms in Pairs (Why or Why Not)?
Yes. It's recommended that the control arms be replaced in pairs. Why? It's because it would be odd for one control arm, such as the right control arm, to be worn out without the left control arm being at, or near, the same level of wear. Remember: the control arm that is okay has travelled the same distance as the worn one, so it's likely that you'll need to replace it soon regardless. This being the case, it'll cost more time and money to have another control arm replacement service performed in the future vs replacing the pair at the same time.
9. Is the Control Arm the Same as the "A-Arm"?
In the automotive service industry, terminology can vary, and different names might pop up for the same part. A control arm is a good example of this, because it's also known as the "a-arm" to some people. Typically, control arms have a triangular or "A" shape when viewed from the side, hence the nickname. Whether you call it a control arm or the a-arm, it's still the same, crucial suspension component.
Need a suspension repair in EHT? If you're having issues with how your vehicle steers or you notice your commutes are less comfortable than they once were, contact Deltona Discount Tires. We're familiar with suspension problems and how to repair them, especially when these issues have a negative effect on the life of your tires. We repair and replace suspension control arms, as well as perform a variety of other suspension repairs to keep your vehicle driving like it should.
Deltona Discount Tires is proud to serve EHT and surrounding areas, such as Ocean City and Atlantic City, New Jersey.
Contact us to discuss your requirements of control arms on a car. Our experienced sales team can help you identify the options that best suit your needs.
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