Trailer Sway: What You Can Do to Prevent It from Occurring

Trailer sway is a common but dangerous phenomenon that can occur while towing trailers of all sizes and kinds. If left uncorrected, trailer sway can result in the tipping of a trailer or even cause the tow vehicle to lose control and crash. Also known as "fishtailing," trailer sway can happen as a result of numerous factors, many of which are preventable by drivers who understand its causes. Below are the causes of trailer sway and what you can do to keep it from occurring the next time you are towing.

Properly load the trailer

Trailer sway is known to occur whenever trailers are not properly loaded and weight distribution is skewed as a consequence. If at all possible, be sure that any load you place on a trailer is evenly distributed from side to side; too much weight on one side can cause uneven stresses that will reveal themselves at the worst moments. These stresses include causing the tires on one side of the axle to grip tighter than the other side, and that can lead to uneven braking and an overall breakdown of stability. If you are placing your load, such as a vehicle, exactly in the centerline of the trailer is impossible, then you can compensate by placing heavy objects on the opposite side. This "ballast" can consist of anything you wish, including cargo and deadweight such as cement blocks.

Not only should trailers be loaded evenly from side to side, but the heaviest part of the cargo should be placed directly over the trailer's axles. If this is not practical, then push the weight forward to keep downward pressure on the hitch. Too far back, and the weight can lift up on the tow vehicle, causing it to lose traction as a result.

Keep the trailer well maintained

Another way to prevent trailer sway from occurring is by keeping the trailer's critical components well maintained. For example, be sure that the brakes on a trailer function as designed and are demonstrating consistent braking force on both sides of the trailer. Uneven braking can cause one side of the trailer to lurch in comparison to the opposite side.

Another component that needs careful attention are the tires of the trailer. Due to the possibility that a given trailer may have spent months in storage, there is a likelihood that tires will develop flat spots from storage and possible rubber cracking. Check the tire pressure at all wheels and be sure that all tires are properly inflated—too little tire pressure can inhibit trailer handling and lead to swaying, Of course, replace tires that are excessively worn or showing signs of deterioration due to storage. Any problems with the tires can lead to sudden movements when trailer sway begins to increase.

Use an appropriate hitch

To prevent trailer sway, the hitch should be level with the trailer, and it should also be of sufficient size and strength to maintain control should swaying start to creep up on the driver. In addition, since the junction between the tongue of the trailer and hitch bears a significant part of the overall load, there should be no doubt about the hitch's ability to carry the weight.

When you are choosing hitches, there are multiple choices available; however, a safe bet when towing a substantial trailer is to use a Class III hitch. These hitches are rated for trailers and loads that don't exceed 8,000 pounds combined. For situations where 8,000-pounds capacity isn't sufficient, you can explore the installation of a Class IV hitch, which can handle up to 18,000 pounds.

Drive responsibly

A big factor in trailer-swaying accidents is a failure of drivers to understand how their towing habits can lead to disaster. Here are several specific things you should do as a tow vehicle driver to protect cargo and human lives.

Use extreme caution when towing in close proximity to semi-trucks—Turbulence can act as a force upon other vehicles and their trailers, and the buffeting can induce swaying.

Avoid driving in stormy or windy conditions—In the same way that truck-induced turbulence can cause swaying, external weather patterns can also lead to unpredictable buffeting. Pull over your car if you are experiencing a temporary burst of wind, but also keep in mind that you may need to make major route changes in long-term events.

React with a plan in mind—Despite your best efforts, trailer swaying can occur at any point during your drive. If it does, you should respond by avoiding panic stops unless absolutely necessary. Keep a firm grip on the wheel and allow the vehicle and trailer to coast to a safe stop.

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