Symptoms
- Trailer wobbles or sways side to side, especially at highway speed or from passing trucks
- Sway seems to get worse the faster you go
- Sway started after loading the trailer differently than usual
Likely causes
- CommonToo much weight behind the trailer's axleWeight loaded too far back reduces tongue weight, which is a major cause of sway.
- CommonIncorrect tongue weight (too low, generally should be around 10–15% of trailer weight)Insufficient tongue weight reduces the hitch's ability to control the trailer's side-to-side motion.
- CommonUnderinflated trailer tiresSoft tires flex more and contribute to instability at speed.
- PossibleDriving too fast for conditions or in strong crosswindsSway tendencies are amplified by higher speeds and wind, even with a well-loaded trailer.
What to do
- If sway starts while driving, ease off the accelerator gradually (do not brake hard or turn sharply) and let the trailer settle before slowing further.
- Once stopped safely, check tongue weight; heavier items should be loaded ahead of the axle, not behind it, aiming for roughly 10–15% of total trailer weight at the tongue.
- Check and correct tire pressure on both the trailer and tow vehicle to their specified ratings.
- Consider a weight-distributing hitch if you're not already using one and your trailer and tow vehicle combination calls for it.
- A sway control device (friction or electronic) can help manage minor sway tendencies but doesn't fix an underlying loading problem.
- Reduce speed for conditions, especially in wind or when being passed by large trucks, since these are common sway triggers even on a properly loaded trailer.
Tools and parts
- Tire pressure gauge
- Tongue weight scale (optional)
Weight-distributing hitch or sway control deviceSearch: “weight distribution hitch for towing”
When to call a pro
If sway continues despite correct loading, tire pressure, and appropriate speed, have a trailer/hitch specialist evaluate your hitch setup and weight ratings.
Safety
Use caution
Trailer sway is dangerous and can lead to loss of control; if it happens, ease off the gas gently, never brake hard or swerve, and pull over once stable to fix the underlying cause before continuing.