Components of a Car Suspension System

close up of car suspension system

Ever wonder what lies beneath? Beneath your car’s body, that is. Between the wheels. Sure, you know there is an engine that produces power and a transmission that transfers torque to the tires, but what about the other stuff? If you drive over a washboard road, what are the parts responsible for smoothing out your ride? Or if you drive through a massive pothole, what components take the brunt of the impact?

The suspension in your car, truck, or SUV is in place to level out your ride over rough road. If your tire sinks into a hole in the road, the job of the suspension is to allow the wheel to travel downward while keeping the body of the car as level as possible. If the road is bumpy, the tires bump up and down, but the suspension keeps the body even.

The suspension has other jobs too. More important than ride comfort is safety. Because the suspension provides constant downward force on the wheels, it makes sure that the tires keep consistent contact with the ground. This helps your car to maintain traction, not only for takeoff (although that is pretty important), but also during braking, and when vehicle weight shifts through turns.

Many components work together to make this happen. So, take a peek into the wheel well and discover the (not so) secrets behind things like knuckles and hubs and stabilizer bar links.

Taking the suspense out of suspensions

The wheels on your car need to be able to spin, to turn right and left, and to travel up and down while the body remains still. To accomplish this, the suspension relies on spring tension, fluid dampening, and articulating arms. Here are examples of typical front-wheel-drive suspension system components. The components found in rear-wheel-drive vehicles may be a little different, but consider this an overview of the most common components.

Obviously, the tires and wheels are connected to the car somehow, and yet they are able to spin freely. The parts responsible for this ability are the hub and bearing. The wheel hub is bolted directly to the wheel and spins inside a set of ball bearings that reduce friction while the wheel is moving.

The hub and bearing assembly is attached to (or housed inside of) the steering knuckle. The steering knuckle is connected by way of a ball joint at the bottom to a bracket or arm that moves up and down (called the lower control arm) and at the top to either an upper control arm or to the strut assembly.

The strut assembly – also known as a MacPherson strut – is a hydraulic shock absorber running through a coil spring. The strut is bolted at the top to the body of the car and rotates on a plate so that the whole suspension can turn. The strut and knuckle are fastened to one another, and both turn or pivot so that the wheel can pivot.

Together, the hubs and bearings, the steering knuckle, the control arm(s), the ball joints, and the struts serve as the structure to hold the car up and the mechanisms to allow the wheels to spin and pivot.

But that’s not all…

Steering you in the right direction

Not all of the parts associated with your car’s suspension are, strictly speaking, suspension parts. For instance, you probably know when you turn the steering wheel, you are engaging several components that turn the car right and left. These components are not suspension parts. They are parts of the power steering system. But steering parts are tied to the suspension parts. They work together. Here are typical steering system components connected to the front suspension:

The tie rods are arms that connect a gear (the rack and pinion, or steering rack for short) to the front suspension. When you turn the steering wheel, a shaft engages the steering rack which, in turn, moves the tie rods from side to side, pivoting the wheels left and right.

At the end of the tie rods are (surprise, surprise) the tie rod ends. These are separate from, but connected to the tie rods, and feature a ball and socket that articulates in several directions to accommodate not only the movement of the tie rods, but also the up and down travel of the suspension.

The tie rod ends are bolted to the steering knuckle. You already know that this component holds on to the wheel (by way of the hub and bearing); it also gets turned by the steering rack/tie rods. Hard to say if this component is a steering part or a suspension part. It is really both.

Stopping to take a brake?

Not only are the steering system and suspension components intertwined, but the brakes are part of the mix too:

The brake rotor is a metal disc attached to the wheel hub that spins along with the wheel. When you press on the brake pedal, hydraulic pressure causes the brake pads to squeeze the rotor so that the wheel (and the car) will slow and come to a stop.

The brake pads are held inside a mechanism called a brake caliper. The brake caliper contains one or more pistons that respond to the hydraulic pressure to force the brake pads against the rotor. And the brake caliper is connected to the steering knuckle.

These brake system components have to be able to travel with the suspension, so they are connected by a flexible rubber hose that moves with the ups, the downs, and turns.

And then some…

That’s a lot of parts just to hold your car up. Well, and to make it steer and stop. To add to the mix are components like the stabilizer bar (or sway bar) and its links that connect it to the control arms, or the drive axles that connect the transmission to the wheel hubs. Trailing arms and lateral arms may be part of the rear suspension. And, of course, the wheels and tires themselves are integral to the suspension.

When any of these components get out of whack – whether due to an impact (like hitting a pothole) or to wear over time – a suspension, or wheel alignment, is necessary. If your vehicle doesn’t handle like it used to, if it pulls to the right or left, lunges when you brake, bounces down the road, or if your tires are wearing unevenly, make sure to have a professional inspection and wheel alignment done to evaluate your steering and suspension systems.

This article is intended only as a general guidance document and relying on its material is at your sole risk. By using this general guidance document, you agree to defend, indemnify and hold harmless Hogan & Sons Tire and Auto and its affiliates from and against any and all claims, damages, costs and expenses, including attorneys’ fees, arising from or related to your use of this guidance document. To the extent fully permissible under applicable law, Hogan & Sons Tire and Auto makes no representations or warranties of any kind, express or implied, as to the information, content, or materials included in this document. This reservation of rights is intended to be only as broad and inclusive as is permitted by the laws of your State of residence.

Shop for Tires
Professionals You Trust. Service Beyond Expectations.

At Hogan & Sons, our highest priority is serving our customers. We are 100% committed to you, our valued customer. We strive to make every part of your experience with us hassle-free and pleasant.

Request a quote