New travel trailer users beware. A big boogieman lurking around the next curve could be your undoing. Trailer sway! The National Highway Transportation Safety Administration reports that about 50,000 trailer sway accidents are reported each year. And many of these are preventable. A bit of sway can ruin your whole day. What causes it? What can result from it? And what can you do to avoid the perils of trailer sway? Read on!
Watch that loading
One major cause of trailer sway is improper loading. Weight in any kind of trailer should be evenly distributed. Put too much weight on the rear of the trailer, the rear of the trailer can turn into the proverbial pendulum. And the trouble is, once that trailer begins to sway, things can get worse in a hurry—jackknifing your tow vehicle, maybe even rolling your whole combination over with disastrous results. Too much weight forward, you can actually pull the front tires of the tow vehicle away from the roadway, making for out-of-control steering and braking.
Avoid trailer sway issues due to improper loading. Ideally, 10 to 15 percent of your trailer’s gross vehicle weight should be on the trailer hitch. Got a 10,000-pound trailer? Then look to see 1,000 to 1,500 pounds on the hitch. How do you know if this is the case? Scale your loaded trailer, ideally knowing the weight on each tire, not just on each axle. When you know the weight of the trailer on its axles, the weight of the tow vehicle while hitched, then you need to unhitch the trailer. Now run the tow vehicle over the scale and weigh it by itself. Subtract the weight of the tow vehicle from your combined weight, then subtract the weight of the trailer tires (combined axle weight). The result is how much weight is resting on your hitch.
Trailer sway when the wind blows
Other causes of trailer sway happen when a big truck passes you. You soon feel that sinking feeling in your gut as your trailer wants to go with that truck. One or two sway bars between your two vehicles and your trailer can knock that problem out. Sway controls are friction control devices that reduce the amount of sway a trailer makes. They’re not expensive, and the average do-it-yourselfer can install them.
Adjusting a sway control isn’t difficult. In many cases, the “factory” adjusted point will work. But if you find too much sway, or too tight when turning, readjust the sway control tensioner a quarter turn “on” for tighter, or “off” for looser. Road test and repeat the adjustment as needed. One thing about sway controls, be sure to turn them “OFF” when you hit an area of wet pavement.
Other causes of trailer sway include tires that are below proper inflation. Check your tires cold every morning before heading out. Too much “foot in the pot,” as Grampa used to say, can also cause dangerous sway. Slow down! And here’s another time to really slow down—as in, park it and wait. Areas of high winds can really cause control problems. If high winds are forecast, beware. If you start to feel out of control, get off the road and wait it out. A 2009 study of commercial towing accidents showed that a 35-mile-per-hour crosswind can exert 3,440 pounds of force on the side of a large rig. You aren’t as big as a semi, but the point is still this—you are bigger than a passenger car, and the wind is bigger than you.
Coming away alive from trailer sway
What should you do if you encounter a case of trailer sway? First, keep your head. A possible inclination is to hit the brakes. Don’t! Get your foot off the accelerator but stay away from the brake pedal—unless you’re going to hit something. Instead, carefully apply the trailer brakes ONLY, by pushing the manual lever on your brake control. Practice this while parked so you know how to quickly find and apply the control. Stepping on the tow vehicle service brake is far more likely to really mess things up, but slowing the trailer and allowing it to bring your combination back into control may save your bacon.
There are a couple of interesting (terrifying?) clips of travel trailers that got into trouble when trailer sway overcame them. Watch it, and listen to the commentary. Don’t let yourself become a YouTube video. Prepare your rig, and yourself, to avoid the dangers of trailer sway.