Trailer Sway: What Causes It & How to Prevent It

As a trailer owner, you should understand what is trailer saw, how it happens, how to prevent it, and what to do if it happens. In this article, I will go over the basics and the steps to take to avoid trailer sway. I will also give you some tips to keep in mind if you encounter trailer sway.

What is Trailer Sway?

Trailer sway is the leading cause of collisions for trailers. It happens when the trailer starts to fishtail or sway back and forth while the vehicle is in motion. This leads to the vehicle crossing back and forth between driving lanes.

If the driver can’t get the vehicle back under control, a crash can occur with another vehicle. The trailer and vehicle could also flip over due to the extreme motion. This can be a destructive and deadly occurrence so you need to take every precaution to prevent it.

We will outline some of the causes of trailer sway in the coming sections. We will also give you some tips for prevention as well as what to do if it happens to you while driving.

What Causes Trailer Sway?

There are several factors that can cause the trailer to sway. Being aware of these factors can help you to understand the trailer sway better and ultimately prevent it. It can also help you to act properly should trailer sway happen to you while driving. Let’s take a look at these factors!

Poor weight distribution

This is the most frequent cause of trailer sway. A common mistake when loading your trailer is to load weight heavier in the back part of the trailer to reduce the tongue weight that your vehicle is actually supporting. If your trailer starts to sway, though, a heavy back end makes swaying more violent and uncontrolled.

Below is a short video that gives a good visual example of this danger. When they distribute the weight well, regaining control is quick and efficient. When the weight is heavier in the back, the trailer sway becomes more extreme and does not neutralize.

Sway-susceptible design

There are a lot of trailers out there with various. Some are more susceptible to trailer sway. Poor design can be an issue with trying to prevent trailer sway. Like we discussed before, weight distribution is vital.

For this reason, be sure you buy a trailer with good weight distribution. Also, be sure you are using the trailer the way the manufacturer intended. These variables will help to avoid trailer sway.

Too much weight

Your trailer has a weight limit. This is not a suggestion! Be sure you are adhering to the weight limit to avoid many headaches. If you go over the weight limit, you will certainly put undue wear and tear on your towing vehicle.

A more dangerous risk, though, is that overweight loads are more likely to cause trailer sway. With heavy loads, the sway is difficult to control and can be destructive.

Strong winds

As you might expect, a strong wind can definitely catch you off guard and start your trailer swaying. Wind does not only come from the weather, though. A passing semi-truck can kick up a big gust of wind that can push your trailer into a sway.

Travel trailers are especially vulnerable to the effects of strong winds. Their size and height make them susceptible to sway when the wind is present. Be ready to react when you see a large vehicle approaching your side.

High speeds

Slow driving is torture for some people. Yet, high speeds can be dangerous when you are pulling a trailer. The faster you drive, the longer it takes to stop.

Unexpected side winds and uneven weight distribution are difficult enough to manage. You may increase these risks if you’re flying down the highway. If you’re going at a reasonable speed, you might be able to control these variables better.

How Do I Avoid Trailer Sway?

Now that we’ve discussed the variables that cause trailer sway, let’s review some ways to prevent it.

  1. Be sure you’re using an appropriate tow vehicle for the weight you want to tow.

There are several things you should consider regarding your vehicle’s weight capabilities.

  • Tow Rating: This is the highest weight your vehicle can tow safely.
  • GVWR: This stands for “gross vehicle weight rating.” When it comes to your engine and suspension, this is the overall weight that your vehicle can hold. GVWR includes tongue and curb weight and inside weight. This includes the weight of passengers.
  • GCWR: This stands for “gross combined weight rating.” It is the highest weight that your vehicle can support for tow rating and GVWR combined.

Make sure you’ve considered your vehicle’s abilities and restrictions. You want to make sure your vehicle’s frame, suspension, engine, and brakes can handle your tow. Driving your trailer is safer when you’ve done the research.

  1. Make sure your vehicle has a Traction Control System

A traction control system keeps an eye on slippery wheels. If your tires lose traction, this system will help the vehicle to stay in control. It does this by cutting back on the power sent to the wheel that is experiencing the traction issue.

  1. Opt for a vehicle with a longer wheelbase

A long wheelbase is known to reduce trailer sway. This is because of the wider length between the tires makes it possible for the truck to be more in control. Similarly, dual rear tires have more traction which is more resistant to sway.

  1. Opt for a towing package

When you buy your SUV or truck, a towing package is often available. It usually includes a hitch, better transmission cooling, and trailer wiring. A good towing package also might include upgraded breaks, batteries, and alternators. A manufacturer-issued towing package gives peace of mind. You will be confident in your vehicle’s towing abilities and also reduce trailer sway.

  1. Steer clear of your maximum towing capacity

You definitely don’t want to go over your weight limit. It’s best to be extra safe and leave about 20-25% of your weight capacity unused. This way, if you miscalculated or if you need to add a few more pounds for whatever reason, you’ll know you’re safe.

  1. Get a hitch for weight distribution

Since the distribution of weight in your trailer is so vital, there is a tool that can help. A weight distribution hitch dispenses the weight of your load across your axles. Trailer sway caused by uneven weight can really be reduced with this type of hitch. These devices, though, do not eliminate the need to stay under your weight limits when towing.

  1. Don’t exceed the trailer’s maximum weight

That’s right. Your trailer has maximum weight ratings just like your towing vehicle. Overloading your trailer will not only affect your vehicle but it may put stress on your trailer as well. It also contributes to trailer sway.

  1. Avoid heavily loading the rear of the trailer

For the safest transport, load most of your cargo in front of the axle closest to the vehicle. Experts have determined that 60% of the weight in your trailer should be toward the front of the trailer.

  1. Double-check your tongue weight

10 to 12 percent of the weight in the trailer should be on the tongue. Make sure you are very aware of the maximum tongue weight and load appropriately.

  1. Slow down…

We cannot stress this enough. You must not speed when you are pulling a heavy load. It may be difficult, but it is much safer to drive slowly and it reduces sway drastically. Keep this on the forefront of your mind since we know that the mind wanders when you’re driving long distances. Safety first!

  1. Try not to make quick maneuvers while driving

Sharp turns, quick stops and fast accelerations should be avoided at all costs. Rapid movements can quickly cause your trailer to sway. Leave a good amount of space between you and the car in front of you. This will reduce your need to brake suddenly.

Try to stay in the right lane whenever possible. This will help you avoid having to change lanes quickly. And, again, drive slowly!

  1. Try not to drive when winds are strong

If you can, postpone driving when wind speeds are very high. If you can’t avoid traveling, be sure you are driving much slower than you normally would. This will help you to react quickly if your trailer starts to sway.

If winds pick up while you are driving, lower your speed slowly and avoid braking to reduce your speed. Pull over if you are not comfortable with the stability of your trailer. It’s always better to be safe! 

  1. Get a brake controller if your vehicle doesn’t already have one

Many towing vehicles come equipped with a brake controller. If yours doesn’t, it is in your best interest to get one, especially if your trailer has an electric braking system. A brake controller gives you a bit more manual control over your trailer’s breaks.

  1. Keep an eye out for early signs of trailer sway

As you probably know, you need to watch your trailer closely as you drive. Watch out for bouncing or rocking in your trailer and take action when you see signs of sway. We’ll give you some tips on what actions to take in the next section.

How Do I Regain Control When Trailer Sway Happens?

If you’re not a professional driver, you will want to take every precaution to avoid trailer sway. Even so, if you find yourself in a situation where your trailer is starting to sway, here are some tips to recover control.

  1. DO NOT brake with your tow vehicle
    1. Recall that quick movements like hard breaking intensify sway and make you lose control.
  2. Use the brakes on your trailer
    1. This is where a brake controller comes in handy. This gives you manual control of the trailer’s brakes and allows you to slow down without using your vehicle’s brakes.
  3. Lower your speed by ceasing acceleration (take your foot off the pedal)
    1. This reduces speed gradually which gives you more control and reduces sway.
  4. Keep the steering wheel steady and straight
    1. Don’t try to compensate for the trailer’s swaying by counteracting with turns of your steering wheel. This could easily deepen the fishtail motion and cause you to lose control.
  5. Keep your speed low until you can pull over
    1. If the swaying stops, don’t just resume your normal speed. You will need to pull over and examine your load. To fix the issue that caused the swaying, try redistributing weight or examining some other factors.
  6. STAY CALM!
    1. Don’t panic. You’ll forget all of these steps you’ve learned to regain control. Take a breath and keep your wits about you.

What About 5th Wheel Trailers?

This is a common question – is sway an issue with 5th wheels? The hitch is mounted in the bed of the truck right between the back wheels. Sway may still happen with a 5th wheel but it is dramatically reduced. When compared to a standard ball hitch, a 5th wheel is much more stable.

Stay Safe Out There, Travelers!

After reading this, it is our hope that you now have a bit more confidence when towing your trailer. Knowing the methods to prevent sway and react to it ensures your safety and the safety of your passengers. Safe travels!

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