What Does A Sway Bar Do?

Have you ever taken a corner a little too quickly? Maybe you felt as if your car was going to tip over? What keeps your car upright and reduces that "sway" feeling is - you guessed it - a sway bar.

The sway bar is an essential component of a vehicle’s suspension and is most commonly found in larger vehicles and even race cars. Let's take a look at what a sway bar is, what it does, and why it's important to the way your vehicle handles.

What Is A Sway Bar and Its Purpose?

Sway bars, also known as anti-roll bars, anti-sway bars, and stabilizer bars, are part of your vehicle's suspension. A sway bar links the right and left sides of a vehicle's suspension system.

The metal bar has a "U" shape and connects the opposite wheels together with short lever arms. Not all have a "U" shape and some can be solid or hollow. Although they can vary in appearance, they all serve the same purpose. So what is that purpose?

It's in the name! A sway bar limits how much your car sways, or more precisely, from leaning to one or the other side. Ultimately, it prevents body lean and keeps all four wheels of vehicle on the ground.

The sway bar is designed to alleviate pressure on a car's suspension and steering system. If you did not have a sway bar, all that tension will cause the swaying effect and if you take a turn too quick, your vehicle can end up rolling over.

How Does A Sway Bar Work?

The way a sway bar works is the same way a torsion spring (a piece of spiraled metal that resists twisting force) does. Each end of the sway bar is attached to a wheel, either both front wheels or both rear wheels. This is so that when one wheel is more elevated than the other, the bar will twist.

The twisting force is applied to counter the lean from a turn by applying force to the other side of the vehicle. Sway bars help stabilize the vehicle by twisting as your vehicle turns; it restores the wheels to the same height and levels everything out. When you've completed a turn and straightened out, so will the sway bar.

If both wheels rise (going over a bump) or fall (moving down a dip) at the same time, the bar will not take effect. Sway bars work only when the car is inclined to lean to one side.

You may think your sway bar is worse for wear with all the twisting it does, but sway bars are designed to handle this force, and many last a vehicle's entire lifetime.

FWD vs RWD vs AWD

Not only does a sway bar reduce body roll in cornering, but it also influences the overall handling of the vehicle, such as oversteering or understeering (which you can tune). Understeering is when a car steers less than the amount commanded by a driver and __oversteering is when the car turns more __than the amount commanded by a driver.

Moreover, sway bars can affect Front-Wheel-Drive, Rear-Wheel-Drive, and All-Wheel-Drive vehicles differently.

Front-Wheel-Drive: FWD cars handle better with rear sway bars and a stiffer rear sway bar will reduce understeer.

Rear-Wheel-Drive: RWD cars handle better with front sway bars and a stiffer front sway bar will reduce oversteer.

All-Wheel-Drive: If you have an AWD that understeers, install a stiffer rear sway bar and if it oversteers, install a stiffer front sway bar.

Different Types of Sway Bars

While all sway bars perform the same function, how they do it varies slightly. You get an active anti-roll bar system and the common solid, hollow, and splined sway bars.

Solid Sway Bar

The most common type of sway bar, solid sway bars are found in more modern vehicles and have a solid "U" shaped metal bar that connects from one wheel to the other. They tend to be heavy and are long-lasting and durable.

Hollow Sway Bar

Hollow sway bars, also known as tubular sway bars, are the same as solid sway bars in all ways except they are not solid, they're hollow inside. This has benefits to vehicles, specifically performance vehicles, as they have a reduced weight.

Splined Sway Bar

Rather than having a "U" shape, splined sway bars are completely straight and can be solid or hollow. They function the same as a traditional sway bar does, but instead spin directly into connecting arms. They're mainly used in racing and performance vehicles.

Active Anti-Roll Bar System

The active anti-roll bar system is an electronic system controlled by your vehicle's electronic control unit (ECU). This piece of technology works with sensors and actuators to change a vehicle's suspension as it turns corners.

Why Use A Sway Bar?

Not only do sway bars improve a vehicle's handling around turns, but they also protect you. It can be uncomfortable or even dangerous for a vehicle to roll too much in turns. By controlling the weight distribution of a vehicle, it aids in keeping it more planted.

Without a sway bar, uncontrolled body rolls can tend to cause the wheel alignment and their camber to change and reduce how well they grip the road. Ultimately, it's important that you use a sway bar at all times. Although many owners of off-road vehicles take their sway bars off for better performance, it's always best to keep them on.

How To Change & Adjust A Sway Bar

If you're wondering whether it's worth purchasing a sway bar or changing your current one, think about what you intend to use it for.

While it's uncommon for sway bars to fail, it's not uncommon for the bushings to wear out. Bushings are cushions made of rubber that absorb road bumps, reduce vibration and noise, and control movement.

Changing bushings requires you to remove the entire sway bar. Changing or adjusting your sway bar is fairly easy. All you'll need is a vehicle jack, jack stands, and ½ and ⅜ drive ratchet sets.

Step 1: Depending on whether you have a front or rear sway bar, jack up either the rear or front of your vehicle.

Step 2: Remove the bolts that connect the sway bar to the links and then remove the bolts that hold the bushings.

Step 3: Once you've removed the bolts, gently pry the sway bar away. Since it's "U" shaped, you won't be able to pull the bar straight out.

Step 4: Now you can replace either the entire sway bar or just the bushings. Once done, reinstall the sway bar with these same steps.

FAQs

What does a sway bar connect to?

Sway bars attach to the chassis of a vehicle and the sway bar's outer ends are connected to the left and right side parts of a vehicle's suspension component that holds the wheel (known as control arms or struts). It stabilizes the vehicle while still allowing the suspension to move.

What happens if I remove the sway bar?

Driving without a sway bar can be dangerous. They're designed to stabilize the car when turning, so removing it may cause more body roll. Off-road vehicles typically remove their sway bar as it improves off-road performance by allowing the vehicle to have greater articulation. However, if you're not off-road driving at least 50% of the time, keep it on.

How do I know if my sway bar needs to be replaced?

It's fairly uncommon for sway bars to break and most last a car's entire lifetime. However, a sign that your sway bar may need replacing is if you hear any odd popping or clunking sounds while driving over bumps. Sometimes you may just need to replace the bushings - especially if they appear cracked or misshapen.

Final Thoughts

All in all, the answer to what a sway bar does is that they twist to keep your car from doing the same.

Every component in a vehicle works in perfect harmony, and now not only do you know what a sway bar does, but why it's important to have one. The introduction of sway bars has not only led to improved vehicle performance but also saving lives.

So, the next time you take a corner a little too quickly, you can thank the sway bar for keeping you upright!

Sources:

https://www.truckcampermagazine.com/factory-tour/2010-tour-hellwig-products/

https://www.yourmechanic.com/article/what-does-a-sway-bar-do

https://practicalmotoring.com.au/car-advice/how-does-a-sway-bar-work-what-is-it-and-how-does-it-affect-my-vehicles-handling/

https://axleaddict.com/auto-repair/Anti-Roll-Bars-How-to-choose-the-right-sway-bar-for-your-car

https://www.streetmusclemag.com/tech-stories/brakes-suspension/lateral-grip-sway-bars-actually-theyre-important/

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