Sway Bars: What You Need to Know
There are many components to the suspension in your vehicle, and sway bars are one of these. While the vast majority of vehicles come with sway bars, the purpose of the sway bar is a little bit different depending on the purpose of the vehicle. If you have ever asked yourself, “What does a sway bar do?”, the first thing to understand is the concept of sway.
What is Sway?
You may have guessed that sway is not good when it comes to vehicles. In its most simple form, sway is the amount of leaning that a vehicle does from one side to another depending on the forces that are acting upon it. Cornering is going to cause a certain amount of sway in a vehicle. No matter what vehicle you are talking about, when it turns there’s going to be a certain amount of lean to the outside. This is sway.
How Does a Sway Bar Work With The Suspension System?
In order to understand the precise functionality of a sway bar, it is important to understand how the suspension system in your vehicle works in general. While different vehicles have different purposes where suspension is concerned, all vehicles have certain commonalities in the suspension system.
For instance, all suspension systems start with the wheels and tires of the car. In terms of the suspension, the tires give the grip that allows your car to turn, decelerate, and accelerate as necessary. This is why tire tread is so vital when driving as insufficient tire tread may cause issues with your suspension system. Tires also absorb some amount of shock from bumps and other problems in the road.
Under the car, the suspension system has springs. These springs help mitigate the shock caused by hitting larger irregularities in the road or bumps. While the tires can absorb a certain amount of shock, springs can absorb more shock from larger road irregularities like potholes.
Suspension systems also have shocks and/or struts in addition to coil springs. These work with the springs. If the car hits a large bump in a road, the spring absorbs the energy, but it is a shock absorber or a strut that actually dissipates the energy. The strut is filled with oil, and this liquid helps dissipate the actual shock. It is here that the car’s bouncing is stopped after hitting a bump or pothole.
Finally, suspension systems involve a variety of bushings, joints, and linkages. The combination of all of these components are what allow the entire suspension system to move in tandem and respond accordingly to any stimulus given by the road surface or vehicle operator.
You may have noticed that we did not directly mention a sway bar as part of the general suspension system of all vehicles. This is because while the majority of cars do have a sway bar, not all of them do. It does depend on the purpose of the car as well as the build.
What is a Sway Bar?
A Sway bar is a long piece of tubular piece of steel that is bent in various fashions and connected to both the left and right sides of the vehicle. Sway bars can be used in front or rear suspension and often on both. A sway bar limits sway as a car corners. In the event that a car is going around a corner or happens across a rough patch of road, there is a certain amount of lean that is naturally generated. A sway bar prevents the car from leaning too much.
At its heart, a sway bar is a torsion spring, or metal that resists twisting.
The sway bar resists this twisting motion and helps to return the wheels back to an equal height; this in turn levels the vehicle. So, for most of your vehicle’s operation the sway bar is doing very little. However, if any force acts upon the car to push one wheel higher than the other, the sway bar discourages this.
In the event that both wheels in the front or the back are undergoing the same amount of force (for example, if both front wheels are in the air due to a bump), the sway bar does nothing.
What is a Sway Bar Link?
A sway bar link is used to connect the sway bar to the vehicle and allow up and down motion to be transferred though he sway bar. Sway bar links can contain bushings and/or ball joints to allow for the range of motion necessary, these components are some of the most common wear items in your vehicles suspension. Both the ball joints and bushings can wear out over time resulting in clunking and the sway bar being less effective in controlling the vehicles sway.
Why do We Have Sway Bars?
The most important reason to have a sway bar is for safety. It can be very dangerous if a vehicle is upended too much in a turn. Aside from the very obvious danger of a rollover, sway bars help keep the vehicle from sliding in turns. In this way, they prevent the wheels losing grip, which can cause a driver to skid. This can make the car harder to control, particularly when turning or braking.
However, sway bars can have problems as well, which is why they are not applied on all vehicles and not applied the same way on vehicles that do have them. A too-rigid sway bar is one of the more common sway bar link symptoms: it can cause the entire car to feel stiff when going over a bump. It also may increase the likelihood of a wheel becoming airborne if too stiff.
Stiffer sway bars are typically found on cars that are likely to encounter high turning forces on smooth roads. A good example of this would be a racing car or a powerful sports car like a Ford Mustang or a Dodge Charger. These cars have thicker rear and front sway bars, as it is assumed that these cars will be driven on smooth roads at high speeds. Therefore, a stiffer sway bar allows these vehicles to take tight corners with less danger of the car losing its grip on the asphalt and becoming airborne.
However, if you are driving an off-road vehicle, it is likely that the sway bar is far less rigid or potentially may not exist at all, depending. For example, a Jeep Wrangler needs to be able to deal with large bumps. Given that the majority of Jeep Wranglers are also driven on smooth pavement they are very likely to still have some form of sway bar, even if far less rigid than that of a racing car. However, Wranglers or other off-road vehicles that are solely dedicated to driving off-road may have their sway bars removed entirely.
Understanding sway bars and how they should be calibrated can help you fine-tune your suspension depending upon the purpose of your vehicle.