Car struts are one of the most important yet often overlooked parts of a vehicle’s suspension system. Like shock absorbers, automobile struts help dampen vibrations; however, they also provide additional functions related to safety, handling, and comfort.
Whether you’re curious about the difference between struts vs shocks or what the strut on a car does, read ahead to get a comprehensive overview of this car part.
What are Struts on a Car?
The strut on a car is a part of the suspension system. It performs the functionalities of the shock absorber, while also offering structural support to the vehicle. While typical car shocks focus on dampening vibrations, automotive struts provide load-bearing functions, supporting the weight and linking the suspension to the car chassis.
In more sophisticated cars, particularly those with the MacPherson suspension design, they even help maintain the car’s alignment for improved tire stability.
Main Functions of Car Struts
As hinted, the struts on a vehicle are an integral part of the suspension, offering various functions—stability, safety, and comfort. This section emphasizes these functions.
Structural Support to the Car Chassis and Weight
Struts provide structural integrity, helping connect the car suspension parts to the car’s frame. They offer the chassis the rigidity needed for balance and safe handling while also helping to maintain even load distribution across the suspension. This structural role completely differentiates them from simple shock absorbers that do not support weight.
Vibration Absorption and Dampening
Like shocks, one of the most important functions of the strut is to dampen vibrations from the road. Each strut in a car contains a shock absorber with a coil spring that helps it absorb vibrations from bumps, potholes, and uneven road surfaces. They help prevent excessive bouncing of the vehicle on the road, making the ride more comfortable. By minimizing vibrations, the springs may also protect other car parts from increased wear.
Maintain Tire Stability
The struts also keep car tires in correct contact with the road surface. Since they are integrated into the suspension geometry, they help maintain the proper angle and position of each wheel. This stability enhances safety at higher speeds, as it promotes better handling during turns and prevents wheels from drifting out of alignment.
Support in Braking
Another function of car struts is to support the vehicle during braking. They reduce the risk of “nose-diving,” a situation where the front end dips sharply when brakes are applied. The added weight transfer struts help ensure tires are firmly on the ground, allowing brakes to work effectively. Consequently, good struts promote safe and reliable braking performance.
Wheel Alignment Support
Beyond just stability, car struts help maintain alignment angles such as camber and caster. These angles determine how a vehicle steers and grips the road. As part of the suspension framework, struts influence alignment settings during wheel installation or replacement. Therefore, if struts are worn or damaged, they can throw off alignment, causing steering issues and added strain on tires.
Components of an Automotive Strut
We have already briefly mentioned some of the parts of an automotive strut. This section emphasizes each component and its role in ensuring optimum performance.
- Coil Spring: The coil springs wrapped around the strut, working closely with the shock absorber to control the vehicle’s weight and height. Like all springs, they are capable of compression and expansion to absorb vibrations and impacts on the road.
- Shock Absorber: This component in the strut performs the actual function of absorbing and controlling vibrations to prevent excessive bouncing. The shock absorber dampens the energy from impact, maintaining stability.
- Strut Housing / Mount: As the name suggests, the housing (or mount) encloses the strut’s internal features. Therefore, it provides structural support and protection to the components of the struts, particularly the coil spring and shock absorber. The mount is a direct link between the car frame and the suspension.
- Bearing Plate: The bearing plate is on top of the strut, allowing smooth suspension movement. It helps the strut rotate with the steering system, reducing friction and ensuring quick response during turns.
- Piston and Rods: The pistons and rods operate together to regulate hydraulic fluid within the shock absorber to dampen suspension movement. They maintain an up-and-down movement through the fluid to provide the resistance needed to control oscillations and transfer force for shock absorption.
- Spring Seat: As the name suggests, the spring seat offers proper positioning and support of the coil spring, securing it in place. It works in conjunction with the bearing plate to transfer load safely to the chassis.
Primary Types of Car Struts
Like cars feature different suspension systems, struts on a vehicle differ, with designs particular to vehicle types and performance—he suspension layout also influences the strut type.
This section discusses the main types of car struts and their unique features.
MacPherson Strut
The MacPherson combines a coil spring and a shock absorber into a single unit, which serves as the upper pivot for steering. Its direct link to the steering system allows for smooth handling and responsiveness. This design makes it compact and lightweight, promoting better fuel efficiency without compromising stability.
In addition, the design allows for simpler suspension geometry, for easy manufacturability and cost-effectiveness. However, the MacPherson strut may be prone to wear and tear, requiring future replacement. Nevertheless, its vast advantages outweigh its shortcomings, making it the go-to option in most passenger cars, particularly their front suspension.
Chapman Strut
The Chapman strut features a long upright strut combining the coil spring and the shock absorber, with a jointed driveshaft forming the lower link. It is also lightweight and operates on similar principles to the MacPherson strut. However, they are less common but are popular in specialized vehicles for their improved handling dynamics and space-saving compact layouts. Therefore, the Chapman strut is more common at the rear suspension of light high-performance vehicles, particularly racing and sports cars.
Coilover Strut
Coilover struts are a performance-focused design for precise suspension tuning. As the name indicates, they integrate the coil spring and shock absorber into a threaded assembly. This orientation allows drivers to adjust ride height, damping stiffness, and rebound characteristics. Consequently, coilover struts are popular in sports cars and custom builds where handling and cornering performance are priorities.
They represent a balance of functionality and customization for enthusiasts who want enhanced control. However, they are more expensive and require professional tuning. Nevertheless, they offer flexibility for racing and performance driving.
Air Strut
Air strut designs are more sophisticated, replacing traditional coil springs with air bags, offering superior ride comfort. They are controlled electronically and can adjust stiffness and ride height on demand, improving handling. This strut design is widely used in premium and luxury vehicles where smoothness and adaptability are important. Air struts also enable “adaptive suspension” systems that change settings automatically based on driving conditions. However, they are highly complex, making them more expensive to manufacture and maintain compared to traditional struts.
Manufacturing Processes for Car Struts Components
Like many car parts, car struts require high precision engineering to deliver strength, durability, and consistent performance. Below are the standard manufacturing processes for this car component.
Forging
Car manufacturers use forging to produce piston rods and structural elements of the car struts. The forging process involves shaping metals under high compressional forces and pressure. This technique alters the metal’s grain structure, providing increased tensile strength, stress resistance, rigidity, and toughness.
Therefore, forged piston rods can withstand the repeated stress of road vibrations and braking forces without cracking or deforming. What’s more? Forging offers superior fatigue resistance to cast or machined parts, enhancing the strut’s durability.
Stamping and Welding
Stamping and welding are sheet metal fabrication processes for strut housing and mounting brackets. In stamping, the machinist presses flat steel sheets into precise shapes, forming the outer casing that houses the damper. On the other hand, welding joins these parts together, creating a strong and sealed structure.
These processes are cost-efficient while ensuring uniformity and accuracy in mass production. Because struts must bear both vertical and lateral forces, automakers rely on welded housings to provide structural integrity that helps the assembly safely carry vehicle weight and maintain suspension geometry.
CNC Machining
CNC machining involves using high-precision machines to remove pieces from a workpiece until the desired shape and structure is achieved. The technique is one of the go-to processes for crafting car parts with tight tolerance specifications, like the pistons and bearing surfaces.
Depending on the specific needs, manufacturers use CNC machines to cut, grind, drill, and shape metal parts. Unlike other processes, it is faster and maintains extreme dimensional accuracy with minimal variation.
Spring Coiling and Tempering
As the name suggests, spring coiling and tempering are the standard methods for creating the coil spring of car struts. The process involves tightly winding steel wires into helical shapes using a specialized machine.
The next step after spring formation is tempering – the heating of the spiral wires to relieve the internal stress and improve elasticity. Tempering ensures that the spring can compress and rebound repeatedly without losing its shape. It is what allows coil springs to offer comfortable rides and the needed structural support.
Heat Treatment
Heat treatments are a finishing process that involves heating and cooling metals under controlled conditions to improve their general properties. Manufacturers may use heat treatment to refine the hardness and fatigue resistance of strut parts, like piston rods and springs.
These treatments enhance the piston’s endurance to constant sliding motion without quick wear. In the coil springs, the process improves elasticity but reduces cracking under repeated compression. Therefore, proper heat treatment helps improve the performance of car struts and other parts under demanding conditions.
Surface Treatment Options
Surface treatments are another finishing option. However, they usually focus on improving the appearance of the manufactured part, but in doing so, they may boost the chemical properties, making the finished part more durable.
Finishes such as powder coating, painting, galvanizing, or anodizing also protect manufactured parts from corrosion and wear, while also improving appearance. These surface treatments extend the service life of struts and reduce maintenance costs, ensuring that the components remain reliable even under unfavorable driving conditions.
Front Struts vs Rear Struts
As the name suggests, front struts are located at the front suspension, with the rear ones at the back. While they serve similar purposes, they differ in functions and importance.
As mentioned, the front struts (especially MacPherson) are more common because they directly link the steering for improved control. Another reason for the vast popularity of the front struts is the increased weight at the car’s front, requiring more precise handling.
Indeed, the rear struts are less common, but they are more common in racing cars where stability, comfort, and superb handling are essential. They absorb vibrations at the rear wheels for extra support and load distribution.
In general, the front struts focus on steering and braking, while the rear struts contribute to improved balance and comfort. Together, they promote stability and control, benefiting the overall driving experience.
Automotive Struts vs Shock Absorbers: What’s the Difference?
Thus far, we have discussed struts and mentioned shock absorbers. One may even think they mean the same thing, since they share similar functions; however, that is not entirely true. This section will explore the differences between these two car parts.
Shock Absorbers: Damping Only
A shock absorber is a unique component that controls spring oscillations. Its role is to prevent the car from excessively bouncing after hitting bumps. The function of the shock absorber is in its name, and its role is limited to vibration control, making it a simpler and less structural suspension part.
Struts: Structural Support and Damping
An automotive strut combines the functions of a shock absorber with other added roles. A typical strut contains a shock absorber and other components such as a coil spring, housing, and mount. Therefore, in addition to dampening vibrations, struts provide structural support (bear vehicle weight) and maintain wheel alignment.
This multi-role makes car struts more critical to both suspension geometry and steering precision. Therefore, while shock absorbers manage vibration alone, struts offer strength and geometry that hold the suspension system together.
Cost and Maintenance Differences
Since struts integrate multiple components, they are generally more expensive. Still, they incur more maintenance and replacement costs than standalone shocks. On the other hand, shock absorbers are cheaper and easier to service. However, the broader benefits of struts make them more efficient, improve safety, comfort, and provide a better fit for modern cars.
WayKen’s Expertise in Automotive Components and Prototypes
WayKen provides one-stop CNC machining solutions for custom automotive parts, including struts. With advanced capabilities in machining and surface finishing, we manufacture high-quality car parts that ensure strength, durability, and accuracy. Our expertise supports both prototype development and low-volume production, helping automotive engineers validate designs and optimize performance.
Conclusion
Like shock absorbers, automotive struts absorb road vibrations and shocks. However, they also anchor the suspension, stabilize braking, and enhance steering precision. From front struts in everyday cars to advanced air struts in luxury vehicles, each design ensures a balance of comfort, safety, and performance.
As car manufacturers look to improve the modern vehicle, struts remain a cornerstone of suspension engineering. Therefore, drivers and custom parts manufacturers must understand that struts are key to unlocking efficiency and promoting a superior driving experience.
FAQs
How many struts does your car have?
The exact number depends on your vehicle’s suspension design. However, most cars have two struts, usually in the front suspension. Some models, especially those with independent rear suspensions, may also have struts in the rear, making a total of four.
Where are the struts on your car located?
In most vehicles, car struts are typically found in the front suspension, integrated with the steering system. However, sports and high-performance vehicles may also feature struts in the rear suspension for extra stability and comfort.
What happens if you drive with bad struts?
Driving a car with worn struts causes poor handling, increased braking distances, uneven tire wear, and reduced comfort. In severe cases, it can compromise steering control, making the car unsafe in emergencies.
