Trailer sway, the terrifying and potentially catastrophic oscillation of a trailer behind a tow vehicle, is often caused by improper weight distribution, with too much weight concentrated at the rear of the trailer. This instability can be amplified by factors such as speed, wind, road conditions, and inadequate towing equipment.
The Anatomy of Trailer Sway
Trailer sway, also known as trailer wobble or fishtailing, is a dangerous phenomenon where a trailer begins to oscillate from side to side behind the tow vehicle. The severity can range from a minor annoyance to a complete loss of control, leading to accidents. Understanding the root causes of this instability is crucial for safe towing practices.
Weight Distribution: The Prime Suspect
The most common culprit behind trailer sway is improper weight distribution. Specifically, having too much weight positioned behind the trailer axle. This creates a pendulum effect, where the rear of the trailer swings easily, initiating and exacerbating the sway. Ideally, 60-65% of the trailer’s weight should be forward of the axle, placing adequate tongue weight on the hitch.
Speed and External Forces: Agitating Factors
While weight distribution is often the trigger, other factors can amplify the wobble. Excessive speed is a major contributor. As speed increases, even a small disturbance can be magnified, leading to a rapid and uncontrollable sway. Similarly, high winds, passing trucks, and sudden gusts can exert forces on the trailer, initiating or worsening the oscillation. The larger the surface area of the trailer exposed to the wind, the greater the potential for sway.
Equipment and Maintenance: Often Overlooked
Often overlooked are the conditions of the tow vehicle and trailer themselves. Worn tires, loose wheel bearings, inadequate suspension, and a faulty hitch system can all contribute to instability. Regular maintenance and inspection are vital for identifying and addressing these potential problems before they become safety hazards. Hitch compatibility is also crucial; using a hitch that is not rated for the trailer’s weight or is not properly installed can lead to catastrophic failure.
Road Conditions: Contributing to the Problem
Uneven road surfaces, potholes, and ruts can all introduce disturbances that trigger sway. A sudden bump or dip in the road can upset the balance of the trailer, especially if the weight distribution is already marginal. Proper tire inflation is also critical for maintaining stability and absorbing road imperfections.
Frequently Asked Questions About Trailer Sway
FAQ 1: What is Tongue Weight and Why is it Important?
Tongue weight is the amount of the trailer’s weight that presses down on the hitch ball of the tow vehicle. It is usually expressed as a percentage of the Gross Trailer Weight (GTW). As mentioned earlier, aim for 10-15% of the GTW as tongue weight to ensure stability. Insufficient tongue weight is a primary cause of sway.
FAQ 2: How Do I Measure Tongue Weight?
You can measure tongue weight using a dedicated tongue weight scale. Alternatively, you can use a bathroom scale and a lever system. Place the tongue of the trailer on the scale and adjust the setup to accurately measure the downward force. Consult online resources for detailed instructions on using a bathroom scale method.
FAQ 3: How Can I Correct Improper Weight Distribution?
To correct improper weight distribution, rearrange the load inside the trailer. Move heavier items forward, closer to the axle and towards the front of the trailer. Secure all items to prevent shifting during transit. Consider using cargo straps, nets, or dividers to maintain a stable load.
FAQ 4: What is a Weight Distribution Hitch and When Should I Use One?
A weight distribution hitch transfers some of the tongue weight from the rear axle of the tow vehicle to the front axle, leveling the vehicle and improving handling. It’s recommended for trailers weighing over 50% of the tow vehicle’s weight or when the vehicle sags noticeably at the rear.
FAQ 5: What is a Sway Control Device and How Does it Work?
A sway control device dampens the effects of sway by resisting the rotational movement of the trailer relative to the tow vehicle. There are two main types: friction sway control and electronic sway control. Friction sway control uses friction to resist movement, while electronic sway control uses sensors and actuators to apply braking force. They are highly recommended for minimizing trailer sway.
FAQ 6: How Does Tire Pressure Affect Trailer Sway?
Incorrect tire pressure can significantly impact trailer stability. Underinflated tires increase rolling resistance and can lead to overheating and blowouts, while overinflated tires can reduce traction. Always check and inflate tires to the manufacturer’s recommended pressure for both the tow vehicle and the trailer.
FAQ 7: What Maintenance Should I Perform on My Trailer to Prevent Sway?
Regular maintenance is crucial. Check tire pressure and tread depth, inspect wheel bearings and brakes, lubricate moving parts, and ensure the hitch is securely connected. Have the trailer professionally inspected annually to identify potential issues early.
FAQ 8: What Should I Do if My Trailer Starts to Sway?
If your trailer starts to sway, do not hit the brakes hard. Instead, remove your foot from the accelerator and gently apply the trailer brakes if equipped. Steer as little as possible, maintaining a straight line. Once the sway subsides, gradually reduce speed and pull over to a safe location to assess the situation and make any necessary adjustments.
FAQ 9: How Does Trailer Length Affect Sway?
Longer trailers are generally more prone to sway than shorter trailers because they have a greater surface area exposed to wind and other external forces. Extra caution is required when towing longer trailers.
FAQ 10: Is My Tow Vehicle Too Small for My Trailer?
Towing capacity is a critical factor. Exceeding the tow vehicle’s rated towing capacity can lead to instability and safety hazards. Check the vehicle’s owner’s manual and the trailer’s weight specifications to ensure they are compatible. If the tow vehicle struggles to maintain speed or control on inclines, it may be undersized.
FAQ 11: Can Weather Conditions Increase the Risk of Trailer Sway?
Adverse weather conditions, such as high winds, rain, and snow, significantly increase the risk of trailer sway. Reduce speed, increase following distance, and be prepared for sudden changes in wind direction. Consider postponing your trip if weather conditions are severe.
FAQ 12: Where Can I Find More Information on Safe Towing Practices?
Numerous resources are available online and in print. The National Highway Traffic Safety Administration (NHTSA) website provides valuable information on towing safety. Additionally, many RV dealerships and towing equipment manufacturers offer training courses and resources on safe towing practices. Consulting with experienced towers and RV technicians can also provide valuable insights and practical tips.