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Do I Need a Sway Bar for My Trailer? Here is Your Answer

Fact checked by Ronal Dowens

Do I Need A Sway Bar For My Trailer

If you are asking yourself “do I need a sway bar for my trailer?” because you are worried that it is just an unnecessary expense then the answer is yes because it is one of the best investments that you will ever make.

Imagine this. You are on your way to the camping trip that you have been planning for months and you are already driving down the road towards your campsite with your camper trailer in tow. Suddenly, a strong gust of wind causes your trailer to sway from side to side uncontrollably.

You try to correct it but counter-steering only made the swaying worse. Now, your truck is also uncontrollably swinging from side to side until your truck and your trailer starts rolling over on the freeway. This is one of the scariest things that could happen to you when you are towing your trailer but you can also minimize it at the very least.

What Causes Trailer Sway?


Did you know that one of the leading causes of trailer-related accidents and the biggest reason why so many camper trailer users quit after just one camping season is trailer sway? Trailer sway is the scary situation where your trailer will suddenly swing from side-to-side while traveling down the highway.

This is one of the most frightening things that trailer drivers can experience but it is preventable. What causes trailer sway? It usually happens when forces applied to the sides of the trailer caused it to move from side to side behind the towing vehicle.

It is also called “fishtailing”. Although the wind is the biggest reason why trailers start to sway, it is not the only thing that you need to watch out for.

Passing Tractor Trailers – One force is the bow wind caused by a semi-truck passing close by, which can also potentially cause your trailer to sway uncontrollably. When a huge truck passes too close to you and your trailer, the turbulent wind that it caused pushes on the side of the trailer.

To make things worse, the vacuum vortex that formed at the tail of the truck will also pull the trailer towards it. This is worse than real wind (not including the winds generated by a tropical depression) because the turbulence will hit the trailer first before the towing vehicle, further magnifying the effects.

Uneven Roads – Another reason why trailers fishtail is the presence of uneven roads that pull the wheels of the trailer to the side. The roads beside active construction zones are often rough, causing your trailer to tilt to the side. To make things worse, concrete barriers are lining the side of the road.

When your trailer fishtails and hits these barriers, it will cause your trailer and the towing vehicle to flip over.

Uneven Load Distribution – Many experienced campers say that trailer sway is caused by uneven load distribution. Putting too much weight on one side of the trailer can cause an imbalance, which will then cause it to swing harder right at the start.

Your trailer will then act like a pendulum. The uneven weight distribution will cause it to swing out farther, making tire blowouts and difficulty steering much more likely. You must distribute the load of the camper in a balanced way, with around 15% of the total weight on or near the trailer’s hitch.

Any less will cause the trailer’s rear wheels to pull forward just when you apply the brakes. With that said, you should also be careful not to exceed the load limit of the trailer or the towing vehicle. All of these problems can be prevented just by using sway bars on your trailer.

How do Sway Bars Work?


Sway bars act like dampers that work horizontally. Two sway bars are installed on opposite sides of the trailer hitch and whenever the trailer starts to move to the side, the sway bars, with the help of friction and the brakes of the trailer, will help minimize the amount of sway.

Sway bars prevent the wind and other forces that cause the trailer to sway from putting too much force on the tow vehicle, making recovery from the swaying possible. Because the tow vehicle can continue moving forward, it will stop the trailer from fishtailing.

Remember, friction sway bars do not completely negate the forces that make the trailer want to topple over. Sudden sharp turns, strong gusts of wind, and the wind vortexes created by a passing tractor-trailer can still cause the trailer to sway, although not as much as they would without sway bars.

The sway bar acts as a damper that prevents the trailer from moving from side to side. You can tighten the sway bars if you feel that your trailer is swaying too much and loosen it if you feel like you are having trouble making turns.

You can also adjust the sways bars independently from each other. If you feel like the trailer swerves to the right, you need to tighten the right sway bar a bit more, and vice-versa.

Do You Need to Purchase After-market Sway Bars?

Sway bars are mandatory equipment installed by default by trailer manufacturers. Inspect your trailer if it already has tension control sway bars, but if it does not, it is not that big of a deal as they are relatively inexpensive to purchase and have professionally installed.

Sway bars always come in pairs (you do not want to prevent swaying in one side only). They also have tension controls that you have to manually adjust depending on the road conditions where you will be traveling.

Be careful not to overtighten the controls as doing so will make the trailer unable to follow through turns. On the other hand, under-tightening will make it feel like you do not have any sway bars at all.

Functions of the Sway Bars


Sway bars use the weight of the trailer to stabilize it. The bars are installed on the trailer’s frame and chassis, and they are usually designed for attaching onto the tongue and the hitch so they can work as one. Sway bars dampen the forces applied on the trailer by using the tow hitch as a fulcrum.

Sway bars can effectively reduce the amount of side-to-side movement of the trailer by bracing the weight of the vehicle against its chassis. The bars distribute the weight of the trailer evenly so that it will not sway too much even if a force is applied to it.

Passing and Turning – If you are always using the steering wheel to constantly straighten the towing vehicle and the travel trailer then it can get pretty tiring, which is not the kind of feeling that you want to experience when driving across the country.

Furthermore, trying to make the trailer curve when taking turns through a winding mountain road can be dangerous when you do not have the proper sway bars installed. When your trailer has sway bars, it will remain relatively stable even when you take sharp turns and when passing slow vehicles in the highway. If the trailer does not sway, the body remains stable, thus preventing excessive wear and tear.

Using Sway Bars on Travel Trailers – There are many different kinds of sway bars available in the market today. Choose the one that fits the size and weight of your trailer. For instance, if you have a large and heavy trailer, you can use a dual-cam sway bar kit.

This sway bar set attaches to the swing arms of the trailer and onto the A-frame beside the hitch of the trailer.

The cams are hooked on both sides of the travel trailer, making swaying side to side almost impossible. When the towing vehicle and the trailer start to make a turn, the cams automatically unlock, making it possible to steer into the turn while still preventing it from swaying intensely from side to side.

On the other hand, if you own a small tongue trailer, the hitches connected to the sway bars will be more than pleasant.

Different Types of Trailer Sway Bars

Hitch Sway Bars – When your trailer has a built-in hitch for weight distribution, it usually also comes with anti-sway bars already attached. These bars keep your trailer stable even at high speeds. How they work involves transferring the weight to the rear axle of the trailer.

If the travel trailer contains over 50% of the total weight then you need to have weight distribution hitch along with travel trailer sway bars to prevent the trailer from fishtailing.

Adjustable Sway Bar There are some sway bars that the driver can adjust externally while within the vehicle. You adjust the stiffness of the sway bars by increasing or decreasing their lengths. This allows you to fine-tune the sway dampening effect to reflect the different road and driving situations without the need to replace the entire sway bar kit.

Tips and Warning Signs

  • If you notice that your trailer sways more to one side, then you can tighten the screw on that side by a quarter of a turn, or until you do not feel any more swaying.
  • If you need to tow a vehicle during wintery conditions, you need to take off the sway bars as it will only make driving difficult.


Nothing can compare to the thrill and excitement brought about by taking your travel trailer out in the open road toward your campsite. However, it can also be a terrifying experience when your trailer would suddenly sway from side to side.

If you are still asking “do I need a sway bar for my trailer?”, the short and sweet answer is a resounding “yes”. This small additional feature does not only make driving with a trailer easier. It might also save your life.

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