Weights, hitches and towing capacity

By the end of this topic you can

• You can find and explain GVWR, GCWR, GAWR and towing capacity for your own vehicle.
• You can estimate and check tongue weight for a conventional trailer.
• You can tell a ball hitch, a weight-distributing hitch and a fifth-wheel hitch apart.
• You can attach safety chains and a breakaway cable correctly.
• You can check whether your state needs a special license class for the trailer you plan to tow.

What you need to know and understand

• GVWR (gross vehicle weight rating) is the most a single vehicle may weigh fully loaded, including passengers, cargo and the trailer's tongue weight.
• GCWR (gross combination weight rating) is the most the loaded tow vehicle and loaded trailer may weigh together.
• For a conventional travel trailer, tongue weight is usually about 10 to 15 percent of the loaded trailer weight; fifth-wheel trailers put more weight on the hitch, often around 20 percent.
• Too little tongue weight is a common cause of trailer sway.
• Safety chains should be crossed in an X under the tongue, with enough slack to turn but not so much that the coupler can hit the road.
• Many states require trailer brakes and a breakaway switch above a set weight; California, for example, uses 1,500 pounds. Thresholds vary by state.
• In most states a regular driver's license covers a personal trailer, but some states require a non-commercial Class A or B license for heavy trailers or large RVs. California requires a non-commercial Class A for travel trailers over 10,000 pounds GVWR and fifth-wheels over 15,000 pounds.

Reading the weight labels

Your tow vehicle has a certification label, usually on the driver's door frame, and the owner's manual lists its towing capacity and GCWR. The trailer has its own label with its GVWR. None of these numbers may be exceeded, and the lowest limit in the chain is the one that counts. A hitch rated for 5,000 pounds on a truck rated to tow 8,000 pounds still limits you to 5,000.

Remember that everything you load counts: people, coolers, bikes, water and propane. A full fresh-water tank alone adds hundreds of pounds. The only way to know real weights is to use a public truck scale with the rig fully loaded for the trip.

• GAWR: the limit for each axle, so spread weight front to rear
• Payload: what the tow vehicle can carry; tongue weight counts against it

Hitch types and when each is used

A ball and coupler hitch is the everyday setup: a ball on a mount in the vehicle's receiver, and a socket on the trailer tongue that clamps over it. Ball size must match the coupler, and the ball rating must cover the trailer weight.

Heavier travel trailers often use a weight-distributing (load-equalizing) hitch. Spring bars shift some tongue weight forward to the tow vehicle's front axle and back to the trailer axles, so the tow vehicle sits level and steers properly. Many come with built-in sway control.

Fifth-wheel and gooseneck hitches mount in a pickup bed, just ahead of the rear axle. They carry heavy trailers more stably but use most of the bed space.

Hitching up: a safe sequence

1. Back the tow vehicle until the ball sits under the coupler, using a helper to guide you.
2. Lower the coupler onto the ball, close the latch and fit the locking pin.
3. Cross the safety chains under the tongue and hook them to the vehicle's chain points.
4. Attach the breakaway cable to the tow vehicle itself, not to the chains or the ball mount.
5. Plug in the wiring and test brake lights, turn signals and tail lights with a helper.
6. Raise the tongue jack fully and check that the rig sits roughly level.

Common mistakes

• Trusting the towing capacity figure alone. Check GVWR, GCWR, axle ratings and hitch rating too, and weigh the loaded rig.
• Loading heavy gear at the very back of the trailer. This cuts tongue weight and invites sway; keep heavy items low and just ahead of the trailer axle.
• Clipping the breakaway cable to the safety chain. If the hitch fails, the cable may not pull and the trailer brakes will not apply.
• Assuming your license covers any trailer. Check your state's rules for heavy trailers, fifth-wheels and towing more than one vehicle.

Test yourself: Weights, hitches and towing capacity

Answer each question, then read the explanation. Questions come in a random order each time.