Trailer Sway: Why It Happens (And How to Fix It Safely)
Trailer sway is one of the scariest towing problems because it can go from “a little wiggle”
to “I’m losing control” fast.
The good news: most sway is preventable. It’s usually a loading and setup issue —
not a “my tow rating is too low” issue.
High-level rule:
Stable towing comes from correct tongue weight, proper loading, good tires, and the right hitch setup.
Tow rating alone won’t protect you from sway.
What Trailer Sway Actually Is
Sway is an oscillation: the trailer starts steering itself left/right behind the tow vehicle.
If it builds, it can push the tow vehicle around and overload your ability to correct.
Sway usually starts when something disturbs the trailer:
a gust of wind
a passing truck
uneven pavement
speed too high for the setup
steering corrections that “feed” the oscillation
The #1 Cause: Not Enough Tongue Weight
A trailer needs enough weight on the hitch to stay pointed straight.
If tongue weight is too low, the trailer becomes “tail heavy” and wants to wag.
Typical tongue weight targets:
Travel trailers: often ~12–15% of loaded trailer weight (general rule-of-thumb).
Too low is the danger zone for sway.
If you load heavy items behind the trailer axles, you reduce tongue weight and increase sway risk.
If you load heavy items forward of the axles, tongue weight goes up (more stable) —
but it can also eat payload fast.
Other Common Causes of Sway
Trailer is overloaded (or loaded unevenly)
Soft or underinflated tires on the trailer or tow vehicle
Worn suspension (rear squat, weak shocks)
Too much speed for the wheelbase/trailer length combo
Incorrect hitch setup (WDH/sway control not set up correctly)
Crosswinds with a tall/boxy trailer
What To Do If Sway Starts
Safety note: This is general information — always follow your owner’s manual and local laws.
If you feel unsafe, slow down and find a safe place to pull over.
If you feel sway building, the main goal is to stop feeding it and reduce the forces causing it.
Hold the wheel steady. Avoid rapid back-and-forth steering.
Ease off the throttle. Let speed bleed off gradually.
Do not panic-brake. Hard braking can make sway worse.
If your trailer has a brake controller: applying trailer brakes (gently) can help straighten the trailer.
Get to a safe stop and re-check loading, tongue weight, and tire pressure.
Put heavy gear low and near the trailer axles (not behind them).
Avoid “tail heavy” loading (rear storage packed with dense items).
Secure cargo so it can’t shift while driving.
2) Get Tongue Weight Into the Right Range
Measure, don’t guess. People are often surprised how their loading changes tongue weight.
Even moving a generator, cooler, or water can shift things a lot.
3) Tire Pressure and Tire Type Matter
Inflate tow vehicle tires and trailer tires to appropriate pressure for the load.
Underinflated tires flex more, which can amplify sway.
Old/worn trailer tires can behave unpredictably under load.
4) Use the Right Hitch Setup
A weight distribution hitch (WDH) can help stability for many travel trailers.
Sway control devices can help — but they are not a substitute for correct loading.
A “level” tow vehicle does not automatically mean you’re within payload/axle limits.
5) Respect Speed and Conditions
Slower speeds dramatically reduce sway risk.
Crosswinds and passing trucks are real — slow down and leave space.
Short wheelbase vehicles generally feel sway sooner than long wheelbase trucks.
Where Payload-First Fits In
Fixing sway often means increasing tongue weight — which improves stability —
but tongue weight comes out of payload.
That’s why “tow rating is fine” can still end badly: you can get stable tongue weight
and still exceed payload or rear axle limits.
Estimate tongue weight vs payload before your trip
Use the calculator to see how tongue weight and hitch hardware affect payload — then verify at a scale.