Dave Helgeson’s knowledge about RVing earned him the title of “The foremost expert on boondocking,” bestowed by RV industry icon, the late Gary Bunzer (The RV Doctor). He and his wife Cheri owned an RV dealership in the Pacific Northwest and spent 29 years overseeing regional RV shows. Dave has also served as advisor to many industry trade organizations. When he’s not out boondocking, you’ll find Dave in the spotlight at RV shows across the country, giving seminars about all things RVing. He and Cheri currently own their fifth travel trailer, with Dave doing all the service, repair and modifications to his own unit.
Travel trailer sway control is a subject every trailer owner should be well versed in. Uncontrolled sway can lead to loss of control of the tow vehicle and travel trailer. The result is extensive damage to both, and the potential of bodily injury, too.
Yes, you will experience sway when travel trailer towing. Knowing the causes of trailer sway and how to control it are key to a safe and enjoyable RVing experience.
Towing a travel trailer can be tricky, and even dangerous if you don’t know how to stop travel trailer sway. If you’ve ever seen your trailer drifting side to side or felt the force of it pulling you all over the road, you’ve experienced sway.How To Stop Travel Trailer Sway, RVBlogger×
The Top 6 Causes of Travel Trailer Sway
Before you can fix a problem like travel trailer sway, you need to know why it happened. Let’s discuss what causes a trailer to fishtail or “sway” when towing. Here are the top six causes of travel trailer sway.
Improper weight distribution within the trailer
Too little tongue weight can cause dangerous sway.
Excessive tongue weight can overload the tow vehicle. This leads to poor handling and sway.
Experts agree that tongue weight should be 10-15% of the total trailer weight.
Unequal weight distribution side to side within the trailer can sometimes lead to handling problems, like sway.
Overloaded tow vehicle
Tow vehicles carrying too much weight on either or both axles can lead to sway. The weight can be a combination of the travel trailer weight, passengers and cargo stowed in the tow vehicle.
Rough and uneven roads can lead to travel trailer sway. This is especially true where heavy vehicles have worn depressions in the road with their tires. The resulting swales can cause sway as your tow vehicle and trailer drift in and out of them while in transit.
Passing large vehicles
Being passed or passing by large vehicles can lead to sway and the need for sway control.
Improper tires or tires that are improperly inflated can lead to trailer sway.
Swirling and driving in side winds can be a cause of trailer sway too.
Easy Ways to Control Travel Trailer Sway
Now that you know the causes of travel trailer sway, let’s review how to manage it under each of those situations.
Improper weight distribution can be a major cause of sway. To make sure the tongue weight of your trailer remains around 15% of the total weight, consider the following when loading the trailer for a trip.
Counter balance freshwater tank weight
Do you travel with the fresh water tank full or nearly full? If so, then consider its location. Since water weighs over 8 pounds per gallon, a full 50-gallon water tank weighs in excess of 400 pounds. This weight can significantly impact the handling of your trailer.
- Is the water tank located over the axles? You don’t have much to worry about, provided you haven’t exceeded the GVWR of your trailer.
- Or is the water tank located in the back of your trailer, say under a bed? If yes, be certain the weight of the water is not reducing the tongue weight below acceptable levels.
- Is the water tank in the front of your trailer? In that case, the added weight of the full water tank might impact the handling of the tow vehicle. This is because too much weight on the back of the tow vehicle can lighten the front end. The results are steering and handling problems. Your front tires may not have enough weight on them to properly steer.
When you do travel with a nearly full water tank, consider counter balancing the weight of the water. This can be accomplished by storing heavy items like canned goods at the opposite end of the trailer from the tank.
Black and graywater tanks can affect tongue weight, too.
For example, if you have a rear bath travel trailer with a 40-gallon black and a 40-gallon grey tank, the combined weight when they are both full can exceed 640 pounds. This weight at the rear of the trailer can definitely lighten the tongue weight on a smaller travel trailer.
What if these holding tank location scenarios are not applicable to your travel trailer? In that case, your only concern is to evenly load the trailer from front to rear. Keep the tongue weight around 15% of the total weight. And when possible, keep heavy items, like canned goods, cases of soda, etc. stored towards the center of the trailer, over the axles.
Pass large vehicles with care
Large vehicles can cause travel trailer sway. To achieve sway control when passing or being passed by large vehicles, move over in your lane as far as possible from the other vehicle. Maximize the air space between the two of you. A larger air space minimizes travel trailer sway between you and the other vehicle.
Maintain your trailer tires
Unmaintained trailer tires are another cause of travel trailer sway. Here are two items to keep in mind when considering sway control for tow vehicle and trailer:
Overloaded trailer tires are dangerous. Exceeding RV tire load range can lead to poor handling and sway. I recommend installing truck tires on the tow vehicle when towing a larger travel trailer.
Avoid trailer towing in wind
Strong and swirly winds lead to drifting and lack of travel trailer sway control. Even if your rig is equipped with a sway control device, it’s best to avoid traveling in windy conditions.
If you must drive in crosswinds on windy days, slow down. Be prepared to correct for powerful wind gusts when steering.
Don’t overload a tow vehicle or travel trailer
Do you know the total towing / carrying capacity of your tow vehicle? What about with the carrying capacity for each axle? As noted above, if you’re not utilizing a weight distributing hitch, you increase the risk of overloading the rear axle. This lightens the front axles, tires and wheels responsible for safe steering.
When steering function is reduced, sway and poor handling follows. And overloading the carrying capacity of any travel trailer is not only dangerous, but can result in lack of travel trailer sway control.
Drive carefully on bad roads
It’s easy to sway and drift because of the swales in the road surface created by large trucks. To counteract it, keep your travel trailer tires centered in the swales. Or, steer to either side of the lane where the road surface is less worn out. This keeps you out of swales and helps avoid travel trailer sway.
What is The Best Travel Trailer Sway Control Gear to Avoid RV Wrecks?
The term sway control is often misunderstood among travel trailer owners. Many times, standard weight distributing hitches, (aka an equalizing hitch) are thought to be sway controls. This is why equalizing bars are often called by the misnomer “sway bars.” Unfortunately that is not how they work. Let me explain.
- A standard weight distributing hitch helps control sway by properly distributing the load between the tow vehicle and trailer.
- But a standard weight distributing hitch contains no mechanism to reduce side-to-side motion of the trailer, the same way a sway control device does.
I purposely listed the causes of trailer sway and methods to reduce or eliminate sway before mentioning sway control devices. This is because during my years of being in the RV business, I often saw sway control devices employed as a band-aid instead of determining the root cause of the sway.
Sway control band-aids result in the travel trailer owner purchasing something they may not have needed. Even worse, a lack of travel trailer sway knowledge can mask a potentially dangerous problem, such as inadequate tongue weight.
Types of Sway Controls
Here are the most popular sway control devices in use today:
Friction sway control
You’ll see that friction sway controls have been around forever. The design makes them easy to understand the principles of operation and are simple to adjust and use.
Friction Sway Control uses friction to resist pivotal movement and thereby works against the effects of induced sway. It operates on the principle of “stiffening” the coupling between the tow vehicle and trailer. The degree of “stiffening” or friction is adjusted to suit various trailer weights and towing conditions . . . It doesn’t prevent the generation of sway (but) simply works to resist the forces once they have started.Draw-Tite Weight Distribution Sway Control, Friction
Weight distributing hitch with incorporated sway control.
As noted above, a standard weight distributing hitch is designed to equalize the tongue weight of the trailer between the two axles of the tow vehicle and the axle(s) of the towed trailer. By doing so, the back of the tow vehicle is not overloaded. This allows the tow vehicle to handle as it should.
Equalizing the weight does nothing to keep the tow vehicle and trailer in a straight line with one another. A weight distributing hitch with incorporated sway control, uses some type of added resistance to keep the trailer in line with the tow vehicle.
With these systems, the trailer is designed to stay in line with the tow vehicle. It does this until an additional external force, like turning a corner, causes it to disengage. Methods used to accomplish this include:
- Cams mounted on the end of the equalizing bars
- Large spring-loaded bearings
- Or, large springs, or a friction surface where the equalizing bar bears on the hanger (aka snap up bracket) on the trailer or other applications.
Check out several examples of weight distributing hitches with incorporated sway control:
Electric brake sway control.
This relatively new sway control device mounts on the trailer, to monitor sway. Then it gently applies the brakes on either the left or right side of the trailer to eliminate sway. This action keeps the trailer going down the road straight.
Tuson Asymnmetric Sway Control
An electric brake sway control manufacturer says this “system automatically detects when your trailer is swaying too much and its connection to your braking system allows you to easily bring everything back under control. They go on to state that “it also helps you to brake just the right amount to get control back over your vehicle without having to slow down to a crawl.”
As noted at the beginning of this article, trailer sway can become uncontrollable resulting in a serious accident.
Don’t think uncontrolled trailer sway can’t happen to you. Take the time to understand trailer sway. Employ the tips and / or the devices listed above. You’ll enjoy a safer and more enjoyable towing experience.
See our Travel Trailer Towing Guide for additional tips.