Trailer Towing Tips: How to Prevent Trailer Sway

Trailer sway

There are few things more frightening while towing your recreational vehicle than sway. A sudden gust, a passing semi truck or a quick steering correction can start your trailer swaying or fishtailing. The loss of control can mean tipping your valuable recreational vehicle or causing a serious accident.

Even the most experienced drivers have lost control of their towed trailers with disastrous results. A brief encounter with sway on the highway can quickly put a damper on your vacation and make you think about putting the camper back in the garage or up for sale. Read on to find out what causes trailer sway, as well as some trailer towing tips to help keep your RV upright. Read on to find out what causes trailer sway, as well as some trailer towing tips to help keep your RV upright.

What causes trailer sway

Any trailer towed with a hitch set behind the rear axle of the tow vehicle can sway or fishtail while driving. The hitch acts as a pivot point in-between the centers of gravity of the two vehicles. Any trailer sway or side-to-side force will turn the vehicle and create an unexpected steering force.

If that sideways force is strong enough it can be more powerful than the road-tire friction for the drive wheels on the vehicle. The result: the tipping over or separation of the trailer and maybe the truck or car too.

Wind and drafts

Some of the main reasons for trailer sway are crosswinds, drafts from passing semi trucks and descending hills using incorrect braking technique, according to Mark Polk in his RV Tech Tips series on RVTravel.com.

The front of trailers are aerodynamic to improve towing gas mileage. The sides aren’t. A 35-mph crosswind could put as much as 3,440 pounds of force pushing on the side of a large trailer, according to a study on commercial vehicle towing accidents by Knott Laboratory in 2009.

Weight and balance problems

Loading too much gear on one side of your camper can unbalance the trailer. Unbalanced trailers swing more dramatically once a sway starts, like a pendulum around its center of gravity.

Balancing weight to the forward and rear is also vital for controlled driving. Between 12 percent and 15 percent of the trailer’s weight should be resting on the tow vehicle’s hitch, according to Bill Estes, writing in Trailer Life Magazine. Any less weight forward may pull up on the tow vehicle’s rear wheels just when you need more traction and control. However, drivers have to be careful not to exceed the tow rating of the hitch or vehicle itself.

Trailer towing tips to help keep trailer sway from happening

The best way to correct trailer sway is to avoid it in the first place. Avoid travel during heavy crosswind weather and be aware of large trucks coming up from the rear to counter-steer their bow wave drafts. A trip to the nearest commercial scale will let you know if you need to move your camping supplies forward or back for the trip.

What products are available to reduce trailer sway

Several hitch designs claim to reduce sway through friction control or weight distribution. Weight distribution hitches use special parts to distribute the tongue weight of the trailer among all of the axles, both tow vehicle and trailer, according to the National Highway Traffic Safety Administration.

Brake control systems allow the tow vehicle to automatically activate the trailer’s brakes when the driver hits the brake pedal. Most have a control lever to manually use the trailer’s brakes without using the tow vehicle’s brakes.

How to help stop trailer sway once it starts

If your trailer starts to sway on the road, the NHTSA recommends activating the manual brake control override by hand. Applying the tow vehicle brakes will generally make the sway worse. Lift your foot from the accelerator but don’t step on the brake pedal unless you’re in danger of hitting something, according to Estes.

Proper equipment, attention to weight balancing and keeping an eye on the weather and passing vehicles will help make sure the only sway you feel on your camping trip is that of the hammock at your campsite.

 

In the event sway does occur, it’s important to know that your RV is protected. Find out about Nationwide’s available RV insurance options today.