Sway Control

Sway control is a trailer hitch system or technology that resists the fishtailing (lateral oscillation) motion that can develop in travel trailers at highway speed.

Why trailers sway

Travel trailers can develop sway because their hitch point (bumper-pull) is behind the tow vehicle’s rear axle. Wind gusts, passing trucks, or uneven loading can start the trailer swinging side-to-side. Without sway control, the oscillation can amplify until the trailer overruns the tow vehicle.

Fifth wheels don’t develop sway because the kingpin hitch puts the connection over the truck’s rear axle, eliminating the lever effect.

Two sway control approaches

1. Friction sway control — a separate device clamped to the hitch and trailer tongue, providing friction that dampens swing motion. Mostly older hitches.

2. Weight distribution hitch with built-in sway — modern WDH designs (Equal-i-zer, Reese Strait-Line, Husky Centerline) include integrated sway control. The spring bars resist sway laterally as well as redistributing weight.

3. Electronic trailer brake controller with sway detection — modern tow vehicles (2018+ pickups) have integrated electronics that apply trailer brakes selectively to dampen sway.

What to confirm at rental pickup

For travel trailer rentals over 4,000 lb:

• Does the WDH include sway control? (Most modern ones do.)
• Is your tow vehicle’s trailer brake controller properly programmed? Some need calibration for the specific trailer.
• Are the WDH spring bars rated for the trailer’s tongue weight?

Without effective sway control, a 25-foot travel trailer can develop sway behavior on a windy highway day that becomes dangerous.

What causes sway despite controls

• Improper loading (too much weight at the rear of the trailer)
• Underinflated trailer tires
• Worn-out spring bars on the WDH
• Misadjusted WDH (heads not torqued to spec)
• Driving over GVWR or maximum tow capacity

If your rental sways noticeably on flat highway, stop and reload cargo or pull over to recheck the hitch.