How Does Car Suspension Work?

Without suspension, driving your car would be a jarring experience. If you’ve ever ridden in a sports car or a large solid axle truck, you might have an idea of how important suspension is to not only the comfort of your car but the handling and towing capabilities it has. 

Suspension systems help control your vehicle’s body movement, isolate the cabin from rough or bumpy roads, and help you accelerate and brake safely. Suspension technology is complex, and in this article, we are going to demystify it, define some terms, and provide you with a better understanding of how it all works. 

What Does Car Suspension Do?

At its core, car suspension helps you keep control over your vehicle while you drive by counteracting the natural physical forces it encounters as you go down the road. 

Road Isolation

The suspension keeps the cabin of your vehicle isolated from the road. Without it, you would feel every bump, pothole, and abnormality as you drive. By bearing the brunt of road impacts, the suspension system keeps the ride of your vehicle smooth and comfortable.

Handling

Cars are big and heavy. When taking a corner, all that mass shifts and moves, which impacts how the car handles. Suspension helps reduce body roll and gives you better control of your vehicle. Not only does this improve the driving experience, it makes the car safer. 

Road Holding

Similar to handling, suspension greatly improves road holding. When we say road holding, we are referring to your vehicle’s ability to keep all four tires in contact with the road at all times. As we described above, the forces put on your car when you accelerate, brake, or take corners are substantial, and the suspension system keeps all four tires planted, helping you to stay in control no matter what you are doing. 

Car Suspension Components

Nowadays, there are a range of individual components that make up vehicle suspension systems. 

Shocks

Shocks are individual shock absorbers, controlling how quickly the springs rebound when you drive over a bump, helping keep the tires in contact with the road. Unlike springs, shocks do not bear any weight. 

Struts

While often compared to or used interchangeably with shocks, struts are an entirely different component. Unlike shocks, which are an individual component serving a very specific purpose, struts are an important structural element of a car’s suspension. Struts incorporate shock absorbers and springs into a robust, weight-bearing unit. Not all cars utilize struts.

Springs

Springs are the core of your vehicle’s suspension. They allow for the up and down movement of the wheels as you drive, and are responsible for supporting the weight of the vehicle. There are several types of springs.

Coil Spring

Coil springs have become commonplace on most modern vehicles. They are normally made from a steel rod bent into a coil shape. Springs have a wide range of stiffnesses and are used on everything from commuter cars to pickup trucks.

Leaf Spring

Leaf springs are an older technology that is still used today on larger vehicles like trucks and SUVs. Leaf springs utilize layers of metal bolted together, with each layer getting progressively shorter. The end result is a stack of metal that looks something like a bow. Stacking different-length metal pieces together helps give the leaf spring progressive stiffness.

Control Arms

Control arms are metal components connecting the chassis to the steering knuckle. These components prevent forward and backward movement of the suspension system, while still allowing the springs to compress up and down. Larger vehicles will have an upper and lower control arm on each wheel, while smaller cars often just have lower control arms.

Ball Joints

Ball joints are the connection point between the control arm and the steering knuckle. You can think of a ball joint as similar to the human hip. A round ball in a socket that allows for multi-directional movement between the steering knuckle and control arm, providing a smoother ride. 

Bushings

Bushings are components usually made out of polyurethane or rubber that help to dampen the movement of joints in the suspension system. 

How Does Car Suspension Work?

Now that we have a solid understanding of the purpose of car suspension and its various components, we can take a look at how the system works. 

Sprung vs. Unsprung Weight

Before getting into how suspension works, we first need to understand sprung and unsprung weight. Unsprung weight consists of the wheels, tires, axles, springs, brake assembly, and the steering knuckle, while sprung weight is everything else (body, engine, transmission, etc.).

It’s important to know the difference between sprung and unsprung weight when talking about suspension since the unsprung components are what “suspends” the sprung parts of the car.

Real Life Example

When you encounter a bump in the road like a railroad track or a dip like a pothole, the unsprung components of the suspension react. In the case of a bump, the spring will compress, the control arms will move up, and the shocks will dampen the impact of the bump. 

The reverse is true when you drive over a pothole. The components will extend down, keeping the tire in contact with the road despite the other three wheels being on a higher surface. 

Working together, the suspension system keeps all four wheels in contact with the ground at all times, no matter what obstacle you drive over. 

Common Suspension Problems

Suspension components are subject to a lot of abuse. Bad roads, aggressive driving, and impact with hazards will begin to wear down on the aforementioned parts of your suspension. Control arms can crack, bushings can wear out, and shocks, struts, and springs can become damaged and stop working as they should. 

Failed suspension components will present in several ways. You might hear bangs or clunks when going over bumps, and if the damage is bad enough it can impact how your vehicle handles. Since the suspension system is integral to the safety of your vehicle, it’s important to get issues diagnosed and addressed quickly. 

Suspension Service at Sun Automotive

Does your car need suspension work? Trust the expert technicians at Sun Automotive in Eugene, Springfield, and Junction City Oregon. With ASE Certified Master Technicians and a lifetime warranty, we stand by our work so you drive with confidence. Give us a call or schedule an appointment online today!