Before you tow anything, two questions matter more than almost any other: is the trailer too heavy for the vehicle, and is the weight on the trailer in the right place? Get either one wrong and the rig can be hard to stop, hard to steer, or prone to sway, the side-to-side wagging that can turn into a loss of control at highway speed.
This article explains the weight ratings you'll see on vehicles and trailers, what tongue weight is and why it matters so much, and what to do if a trailer starts to sway. There's a tongue weight calculator below to check your own setup.
The ratings that matter
Vehicles and trailers come with several weight ratings. They're usually printed on a sticker inside the driver's door jamb, in the owner's manual, and on a plate or sticker on the trailer's frame or tongue. The key ones:
| Rating | What it means |
|---|---|
| Towing capacity | The maximum trailer weight the manufacturer says the vehicle can pull, when properly equipped. |
| GVWR (Gross Vehicle Weight Rating) | The maximum the vehicle itself can weigh, including passengers, cargo and the trailer's tongue weight. Trailers have their own GVWR too: the most the loaded trailer may weigh. |
| GCWR (Gross Combined Weight Rating) | The maximum the loaded vehicle and loaded trailer can weigh together. |
| Payload | How much weight the vehicle can carry, including people, gear and tongue weight. |
| GAWR (Gross Axle Weight Rating) | The maximum weight each axle can support. |
| Hitch rating | The maximum trailer weight and tongue weight the hitch, ball mount and ball are rated for. |
You have to stay within all of them at once. A common surprise is running out of payload before you reach the towing capacity. A truck rated to tow a heavy trailer may not have the payload for that trailer's tongue weight plus a cab full of people and gear.
Remember too that the weight that counts is the loaded weight. A camper's dry weight from the brochure doesn't include water, propane, food and gear, which can add a lot. A public scale, like those at many truck stops, is the most reliable way to know what you're really towing.
What tongue weight is
Tongue weight is the downward force the trailer's tongue puts on the hitch ball. It depends on where the trailer's load sits relative to its axles. Weight ahead of the axles pushes the tongue down. Weight behind the axles lifts it.
For a typical bumper-pull trailer, a common guideline is that tongue weight should be about 10 to 15 percent of the total loaded trailer weight. Fifth-wheel and gooseneck trailers carry a larger share on the hitch, commonly quoted at around 15 to 25 percent. Always check your vehicle's and trailer's own recommendations.
Why tongue weight matters
Too little tongue weight is the dangerous one. If too much of the load sits behind the trailer's axles, the trailer becomes unstable and prone to sway. Small disturbances, like a gust of wind, a passing truck or a quick steering correction, can start the trailer wagging side to side. Instead of settling down, the swaying can grow, and it can pull the back of the tow vehicle around with it.
Too much tongue weight overloads the tow vehicle's rear axle and lifts weight off the front wheels. That reduces steering grip and braking at the front, can make headlights aim too high, and can push you past the vehicle's payload or hitch rating.
Check your tongue weight
Uses the common 10–15% guideline for bumper-pull trailers. Your vehicle, hitch and trailer manufacturers' limits always take priority. Tongue weight can be measured with a tongue weight scale or at a public vehicle scale.
How to load a trailer
- Heavy items low and slightly forward of the axles. This keeps the center of gravity low and puts the right share of weight on the tongue.
- Balance side to side. An uneven load makes the trailer lean and pull.
- Secure everything. Load that shifts while you drive changes the balance, sometimes suddenly.
- Don't overload the back. Heavy items at the rear, such as a spare tire, generator or bike rack on the back bumper, reduce tongue weight and increase sway.
Trailer sway, and what to do about it
Sway is when the trailer starts moving side to side behind the tow vehicle. It's most likely at higher speeds, in crosswinds, when large vehicles pass, going downhill, and with too little tongue weight. If it happens:
- Ease off the accelerator. Let the rig slow down gradually.
- Hold the steering wheel steady and straight. Don't try to steer against each swing. That usually makes it worse.
- Don't slam on the tow vehicle's brakes. Hard braking on the truck alone can make the trailer push and swing further.
- If you have electric trailer brakes, applying the trailer brakes alone, gently, using the manual control on the brake controller, can help pull the trailer back in line behind you.
- Once it's under control, pull over when it's safe and find out why. Check the load balance, tire pressures and hitch.
Prevention is far better than recovery. Correct tongue weight, proper tire pressures, sensible speed, and for heavier trailers, a weight-distribution hitch or sway-control device can all help. Many tow vehicles also have electronic trailer sway control built in.
Trailer brakes
Heavier trailers need brakes of their own. Without them, the tow vehicle's brakes have to stop the whole combined weight, which takes much longer and wears the brakes quickly. Most U.S. states require brakes on trailers above a certain weight, often somewhere between about 1,500 and 3,000 pounds, depending on the state. Electric brakes need a brake controller installed in the tow vehicle, which you can adjust so the trailer brakes do their share without locking up.
Weight and stopping
Even within every rating, a trailer makes your rig much heavier, and a heavier rig takes longer to stop and longer to speed up. Leave much more following distance than you would without a trailer, start braking earlier, and allow more room when merging and changing lanes.
Practicing in The Trailer Parker
The Trailer Parker lets you choose a Light trailer (a utility hauler), a Medium trailer (a car hauler) or a Heavy trailer (a boat hauler). The weight changes how quickly the rig speeds up and slows down, not how points are scored. With the Heavy trailer, you'll find you need a lighter foot on the accelerator and earlier braking to stop exactly where you want, the same habits that matter on the road. Pick the weight closest to what you really tow, or go heavier to practice smooth control.