Your trailer sways at high speeds because small disturbances (wind, bumps, lane changes) get amplified by inertia and an unstable load, making the trailer oscillate back and forth, a dangerous situation that reduces control and can lead to rollovers, often worsened by poor weight distribution, high speeds, and crosswinds. Factors like heavy rear-loaded cargo, low tongue weight, and incorrect tire pressure reduce stability, while strong winds or large passing trucks act as triggers, especially when the trailer is already prone to movement.
Controlling trailer sway
There are a number of things that can cause trailer sway, main causes listed first: Overloading, insufficient weight distribution, insufficient tongue weight percentage, towing trailer nose up, unbalanced tire pressures, tow vehicle tire sidewall flexing, mechanical (bearings, axles, struts, springs, etc) failures.
Immediate Fixes to Reduce Sway During Your Trip
The ideal tongue weight is between 10-15% of the fully loaded trailer weight. Too much will diminish your vehicle handling, while too little will cause trailer sway.
How Can I Tell if My Tongue Weight is Over 15%? Too much tongue weight means that most of your load is on the front end of your trailer and you exceed 15% of your GTW on the trailer tongue.
To further stabilize your trailer while loading it, wheel chocks are recommended. Simply chocking the wheels will help ensure your trailer won't move or roll while loading cargo.
At what speeds is trailer sway most likely to occur? Sway risk goes up as you travel faster. Most sway happens above 50 mph, but dangerous sway can happen at lower speeds if conditions are right. Highway speeds increase the effects of crosswinds, turbulence, and bumps, so a stable rig is even more important.
Travel trailer hitch height should match the height of your trailer's coupler to keep both units level. This ensures even weight distribution, safe braking, and smooth towing, no tilt, no sway, no guessing.
Tips For Safely Recovering from A Fishtailing Incident
If you can, keep your steering wheel pointed straight ahead and slow down by calmly letting your foot off the gas pedal. If you have trailer brakes or a brake controller, manually apply this feature using a smooth motion. This often will alleviate any swaying.
Recognizing The Symptoms Of Axle Trouble
Common Problems or Mistakes to Avoid
- Incorrect tongue weight: too light causes trailer sway; too heavy overloads the rear axle and reduces steering and braking effectiveness. - Assuming the trailer's empty or nominal weight yields safe tongue weight without measuring after loading and hitching.
Underinflated or mismatched tires increase the risk of swaying, especially on highways. Use a digital tire gauge for accuracy, as visual checks can be misleading. Inspect each tire for tread wear, bulges, or cracks. Uneven tread can indicate alignment problems or worn suspension parts, both of which contribute to sway.
62 to 66 mph. full ones vary speed to far. Alfred Stobart when I had my Ram 1500 pulling my 17' Casita travel trailer (3000 pounds), I would routinely be at 70 mph with no issues. Now that I'm towing her with an SUV, I keep it at 60-65 max.
Rear Weight: Position about 60-65% of the load in front of the axle, with the remaining 35-40% behind it. Side-to-Side Balance: Ensure the weight is evenly spread from left to right to avoid leaning and uneven tire wear.
Trailer sway is the side-to-side movement of a trailer that occurs when it doesn't follow directly behind your tow vehicle. A small amount of sway is normal, especially above 45 mph, but it becomes dangerous when it reacts too much to steering and starts to fishtail.
Check Your Vehicle's Tow Rating
Every vehicle has a maximum tow rating set by the manufacturer. Find it inside your owner's manual or on the manufacturer's website. If your loaded trailer weighs more than this number, your trailer is too heavy. No guesswork needed.
To tow a trailer safely, you must do so with a level trailer and tow vehicle. Incorrect trailering heights and angles can negatively affect how your rig pulls.
The "80 towing rule" is a widely followed safety guideline suggesting you should not tow a trailer heavier than 80% of your vehicle's maximum towing capacity, creating a buffer for miscalculations, varied terrain (hills/declines), and to protect your vehicle's brakes, transmission, and suspension from excessive wear, though some manufacturers set lower limits or have specific rules like 80 km/h speed restrictions. It's a common-sense measure for safer towing, giving you a margin for error beyond the manufacturer's official limits.
The 60/40 trailer rule is a crucial guideline for safe towing, stating that 60% of the total cargo weight should be loaded in the front half of the trailer (ahead of the axle centerlines) and 40% in the rear to ensure stability and prevent dangerous trailer sway. This weight distribution creates proper tongue weight (weight on the hitch), preventing the trailer from fishtailing or lifting the tow vehicle's rear wheels, which can lead to loss of control.
Generally speaking, the speed limits to observe when towing a caravan are 10 miles an hour slower than if you were driving in a car alone. That means on a motorway where the limit is 70mph, you should drive at no more than 60mph. On a dual carriageway where the limit is 60mph, you should stay below 50mph.
How do I stop my trailer from swerving? Slow down gently and as much as possible by taking your foot off the accelerator and letting the motorhome or trailer fall back into place behind the towing vehicle. Don't try to steer out of the situation in an attempt to correct the sway.
Total Trailer Weight
To reduce trailer instability and sway, most of the cargo weight should be placed toward the front of the trailer – ahead of the trailer axles – and evenly distributed side-to-side.
The trailer can sway back and forth and become uncontrollable at high speeds. On the other hand, excess tongue weight can cause the back end of the vehicle to sag, negatively affecting the vehicle handling, driver visibility, and the effectiveness of the vehicle's brakes.