Towing: What You Need to Know


Towing is not as simple as hitching up a trailer and taking off. It’s important to understand how weight has an impact on your tow vehicle, as well as your trailer, and knowing the function of the major towing components. In this article, we’ve defined the main terms associated with towing, including terminology to do with weight and weight capacities, the towing equipment, as well as hitch classes – what defines them, along with how to determine the hitch class your vehicle has. If you’re still unsure about a term, please feel free to call our experts at 888-651-3431 and they would be happy to answers any questions you might have.

Vehicle Weight Terminology

Vehicle Weight Terminology

Gross Vehicle Weight Rating (GVWR)

This is the maximum amount of total weight that your specific vehicle model can handle safely, including the driver, passengers and cargo. This number is set by the vehicle manufacturer.

  • To find: Look at the information panel inside the driver’s side door, or refer to your owner’s manual.

Gross Vehicle Weight (GVW)

This is the actual weight of your vehicle including the driver, passengers, cargo and fuel.

  • To find: Curb weight + driver weight + passengers weights + cargo weight + accessories weights, or weigh your fully loaded vehicle at a weigh station.
  • Note: The gross vehicle weight should always be lower than the gross vehicle weight rating.

Towing Capacity

This is the maximum weight your vehicle can tow using a tow-on-the-ball configuration.

  • To find: Gross Vehicle Weight Rating / Gross Vehicle Weight

Curb Weight

This is the empty weight of your vehicle without cargo, passengers, or accessories. The curb weight established by the manufacturer usually doesn’t take extra options into account, such as sunroofs, so weighing your car will be the most accurate way to determine the curb weight.

  • To find: Weigh your empty car with all fluids topped up. Three places it might be noted are inside the driver’s side door, in your owner’s manual, or stamped on the engine plate.

Trailer Weight Terminology

Trailer Weight Terminology

Gross Trailer Weight Rating (GTWR)

This is the maximum amount of total weight that your specific trailer can handle safely, and it includes the weight of the trailer including all cargo. This number is set by the trailer manufacturer. This number also determines the class of the trailer.

  • To find: It should be on a placecard somewhere on the trailer.

Gross Trailer Weight (GTW)

This is the actual weight of the trailer plus all cargo.

  • To find: Trailer weight + cargo weight, or weigh your fully loaded trailer at a weigh station.

Trailer Weight

This is the actual weight of the empty trailer.

  • To find: It should be on a placard somewhere on the trailer, or you can weigh your empty trailer at a weigh station.

Payload Capacity

This is the total weight that the trailer can safely carry. It is set by the manufacturer.

  • To find: Gross Vehicle Weight Rating – trailer weight

Hitch Class

Hitch classes are separated by their maximum weight capacity rating and receiver opening size. Classes range from I to V, and each class has its own unique capacity and applications.

  • To find: Read the label on your hitch, or measure the size of the opening.
Class Basic Use Size of Opening Gross Trailer Weight (lbs) Tounge Weight Capacity Common Tow Vehicles Used to Tow
I Light-Duty 1.25" 2000 200 Passenger cars, small crossovers Motorcycles, small utility trailers, small boats
II Moderate-Duty 1.25" 3,500 350 Mid-sized sedans Mid-sized boats, small campers, snowmobiles
III Versatile/Mix 2" 3,500-6,000 350-600 Pickups,minivans, full-size SUVs Mid-sized boats, mid-sized campers, boats, utility trailers
IV Heavy-Duty 2" 10-12,000 1,000-1,200 Large pickups, SUVs Heavy loads, large campers, boats, toy haulers
V Heaviest-Duty 2.5" 16-20,000 1,600-2,000 Heavy-duty vehicles, commercial trucks Large board, full sized campers, equipment trailers

Towing Weight Terminology

Please note: Most components will have their maximum weight capacity ratings etched or labeled on them. Read the ratings of all components and use the lowest rating to determine the maximum weight capacity that you can safely tow.
Fifth Wheel and Gooseneck

Fifth Wheel and Gooseneck

A fifth wheel hitch connection can be found inside the bed of some larger pickup trucks, or in the rear of semi-trucks. It’s designed to connection larger trailers such as full size RVs, semi-truck trailers, horse trailers and more. Similarly, gooseneck connections are a hitch ball located in the bed of larger pickup trucks.

Hitch Adapter

A hitch adapter fits into the receiver tube of your hitch to convert it from a smaller opening to a larger one or vice versa.

  • Please note: Using a hitch adapter may reduce the overall capacity of your towing system.

Hitch Extender

A hitch extender fits into the receiver tube of your hitch to add clearance length for your tow vehicle’s bumper.

  • Please note: Using a hitch extender may reduce the overall capacity of your towing system.
Hitch Ball

Hitch Ball

Also known as a trailer ball or coupler ball, the trailer ball attaches to the ball mount and comes in many sizes. The trailer couple will mount and lock into place over the ball. Sizes include 1-7/8”, 2”, 2-5/16”, and 3” (in rare cases).



The coupler is the locking mechanism that connects the trailer tongue to the hitch ball and it must match the hitch ball size exactly.

Safety Chains

Safety Chains

Safety chains connect the trailer tongue to the tow vehicle. They are the backup connectors in case the coupler or ball fails. Two are required, and they have to be attached to their own retainers.

Hitch Pin

The hitch pin locks the ball mount into the hitch tube. It is usually manufactured in steel for strength.

Trailer Wiring

Trailer Wiring

Trailer wiring is used to mimic your tow vehicles turn signals and brake lights. By law, trailer lights must be connected to your tow vehicle, and this requires a trailer wiring harness. Typically, the wiring uses four to seven wires to control the basic lighting and brake light functions.

Weight Distributing Hitch

Weight Distributing Hitch

A weight distribution hitch is used to haul extremely heavy loads using a conventional hitch receiver. It distributes weight evenly between the rear and front wheels of the tow vehicle by attaching spring bars to the vehicle’s frame.

Sway Control

Sway Control

A sway control kit is designed to dampen the side-to-side fishtailing caused by a trailer.

Additional Information

Before towing, please review our important towing safety tips.

If you are interested in using your hitch mount to transport something other than a trailer, check out our hitch-mounted accessories for hitch-mounted cargo options like bike racks, cargo carrier, wheelchair and scooter carriers and motorcycle carriers.