NHTSA shows that approximately 50,000 accidents related to trailer towing occur each year. The majority of these accidents were due to trailer-sway.
While there are simple tricks and tips to promote anti-sway, the best way to control trailer sway is by using a weight distribution hitch. We will cover common questions and important cautions to take when it comes to trailer sway. Let’s get to it!
What is trailer sway and why is it dangerous?
Trailer sway occurs due to some sort of disturbance to the trailer that causes the trailer to move side to side. Some of the most common disturbances that cause trailer sway are wind, side-wind from passing vehicles, and uneven weight distribution.
It doesn’t take very much for a serious accident to happen when trailer sway occurs. On average, it takes about 3-4 seconds from the time the driver notices the trailer sway before an accident could occur.
What Not to do when trailer sway occurs
Acting quickly when trailer sway occurs is crucial. However, you can make the sway worse by taking the wrong approach. The following are actions that should not be taken whatsoever when trailer sway occurs.
- DO NOT press on tow vehicle brakes
- DO NOT overcorrect the steering
How to control trailer sway
Precautions we suggest taking BEFORE towing:
- Assure that the tongue weight is in the safe range of 10-15%
- If possible, use a weight distribution hitch
- Check weather conditions, consider changing your travel plans based on high winds, rain/snow storms etc.
- Make sure all tires have sufficient tire pressure.
What to do WHEN trailer sway occurs:
- The first thing you should do is let your foot off the gas. Remember, do not brake on the tow vehicle! Allow the vehicle to slow down on its own.
- Once you notice that your speed has decreased, manually apply your trailer brakes if you have them. Do this slowly and carefully.
- Keep your steering wheel straight, avoid the urge to over-correct as this will make the sway worse.
- As a last resort, you may attempt to accelerate quickly when trailer sway occurs. Keep in mind, if you do not speed up fast enough, this will only worsen your condition and can make the sway completely out of control.
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Trailer sway and high rotational moment of inertia
One of the most common issues that causes trailer sway has to do with a term you probably have not heard before (or at least not in regards to towing a trailer.) This term is called “high rotational moment of inertia.” While this sounds like a complex scientific concept, it is actually simple to grasp. To cover this topic in simple form, all you need to know is that there is an axle of rotation on a trailer, and when there is a large amount of mass away from this rotational axle, turning becomes a hazard with the trailer sway that will follow.
Now, this is not a difficult adjustment if you are aware of this concept causing the sway. Take the example of towing a Uhaul trailer behind your truck. In the trailer, you’ll have lighter items such as picture frames, clothing boxes, pillows, etc. You’ll also have heavier items like furniture and TV’s. You will want to strategically place the heavier items right around the rotational axle so that the moment of inertia is not as high because the mass is not spread out across the trailer.
To make this concept even easier to understand, imagine a spinning top, the larger the mass of the spinning top, the longer it will spin. Think of the rotational axle of the trailer as the spindle of the spinning top, and the mass in the trailer as the tongue of the spinning top. Keep the mass tight and centered!
So, what is a weight distribution hitch anyway?
A weight distribution hitch distributes tongue weight. When a trailer is hooked up to a tow vehicle, naturally a lot of weight will be placed on the end of the tow vehicle. Using a weight distribution hitch will ensure that this weight is distributed evenly across the tow vehicle and the trailer, allowing the tongue weight to be in the safe range of 10-15% Here is a video demo of what we are talking about, if you’re into that.
What are the risks of towing without a weight distribution hitch?
Without a weight distribution hitch, tongue weight can either be too much, or too little. When tongue weight is too much, the mass on the trailer is too far forward, this forces the tow vehicle and trailer to act as a “teeter totter.” Weight is lost off of the front axle which can throw off the alignment, then the geometry of the tow vehicle is changed, and the tires will not align properly. Misalignment leads to trailer sway.
Too little tongue weight means that the mass on the trailer is too far back, this loosens up everything attached to the tongue of the trailer such as the coupler and hitch. The trailer will rock side to side because of the lack of friction.
Ball joints: if you are higher or if it is loosened it makes the front end unstable if there is any kind of wind.
Whenever possible, you should use a weight distribution hitch to reduce these issues.
Controlling trailer sway with a weight distribution hitch
A weight distribution hitch lifts up on the back of the tow vehicle and acts as a wheel barrow, pushing the front axle of the tow vehicle back down to stock weight. As the front of the vehicle is pushed down, the steering is tightened, making the tires drive straight with ease, reducing trailer sway dramatically.
There are four areas of sway control that the weight distribution hitch will interact with. When the spring arms on the hitch are being lifted up, there are two sockets that they are being pressed into. Each socket meets a metal clamp, making it so that it would take a lot of force to create sway. These are the first two areas of sway control.
The other two areas of sway control are the two brackets that sway forward and back, creating friction to reduce sway coming from the end of the trailer hitch.
Having four different areas of sway control is your best bet at reducing sway. With a weight distribution hitch, the trailer has to overcome the friction coming from the metal clamps, and then even if that does happen, there is even more friction in the trailer brackets to stop it.
Here is a simple visual to point out the areas of sway control on the True Tow Weight Distribution Hitch from Weigh Safe:
Bottom line: If the steering is tight, and everything is aligned, trailer sway reduces.
How to know you need a weight distribution hitch
While the answer to this question varies, a good rule of thumb is to use a hitch any time the weight of what you are towing starts to outweigh your vehicle’s weight by one-half. For example, if your vehicle weighs 6,000 pounds and you are towing a trailer that is more than 3,000 pounds, you will need a weight distribution hitch in order to control sway. This will allow you to drive with peace of mind, knowing that you have prepared for a safe ride by using the right equipment.
Here are additional scenarios to look out for to indicate that a weight distribution hitch would be necessary:
- If your front end is floating
- If you are over your vehicle ratings such as GVWR, GCWR, Cargo Capacity
- If you’re above your max tongue weight
What sets apart the weigh safe weight distribution hitch?
Weigh Safe uses true tow technology which accurately measures tongue weight for you. Our live adjustment system and built in gauge makes it so that you can tow with peace of mind. We are committed to creating a safe, convenient, and simple towing experience for our customers.
Currently, we sell two sizes of our weight distribution hitches. To know which size hitch to buy, check out the “specifications” section on both of our hitches to see the differences and which best suits you.