Trailer Sway Control

Trailer sway can be caused by crosswinds, a passing tractor-trailer, incorrect trailer loading, and uneven road surfaces. Whatever the cause, depending on its severity, trailer sway can be anywhere from an annoyance to the cause of an accident. We offer two ways to deal with sway: prevent it from increasing if it occurs with a bolt-on, independent sway control device, or keep it from happing in the first place with a Weight Distribution (WD) hitch that has built-in sway control features.

When a trailer sways, it pivots on the trailer ball. A sway control device connects between the hitch and the trailer to dampen the pivoting motion. The sway control housing contains friction material that rubs against a telescoping bar, which resists movement when the trailer starts to sway. The friction material is similar to the type used on brake pads. The level of friction and sway control can be set using an adjustment on the housing. An On/Off lever allows sway control to be turned off when backing up or when towing on slippery roads.

A typical sway control kit consists of the sway control unit, a ball mounting plate that attaches to the trailer, the sway control trailer ball, and hardware. Sway control kits are customarily used in conjunction with WD hitches and the weight distributing ball mount generally comes with the sway control ball mount attached. Kits usually include a weld-on tab or adapter to mount the sway control ball if not included with the WD hitch or if the sway control unit will be used without a WD system. We also carry ball mounts that come with a sway control ball mount tab attached. Sway control kits can usually be installed on either side of the trailer, and two, one on either side, are recommended for large trailers.

Because trailer sway can be caused by incorrect trailer loading, using a WD system to evenly distribute the load can alleviate sway, but a standard WD system will have no effect on trailer sway caused by crosswinds. However, installing a WD system with built-in sway control can prevent trailer sway regardless of the cause. The method for controlling sway varies but all work to hold the trailer steady when driving on the highway, yet allow easy turning. Some systems use dual cams that attach to the trailer frame and to the ends of the spring bars and lock to keep the trailer steady and unlock for turning. These cams are fully automatic and self-centering, and the stronger the sway force, the more the dual cams will counteract.

On other systems the spring bars fit into sway control brackets mounted on the trailer frame instead of conventional lift brackets and chains, to hold the bars in place and keep the trailer aligned. The brackets may also have integrated friction pads that hold the spring bars in place and prevent the trailer from swaying. The bars are also held tightly within the head assembly, and some systems use a spring and cam system that maintains pressure to prevent sway when the tow vehicle and trailer are driving straight down the road, but relaxes to allow turning. Unlike independent sway control devices, WD systems with sway control do not have to be disengaged when backing up.