If you already have a tow vehicle

If you already have a tow vehicle, look up its tow rating—size, maximum loaded weight, and maximum tongue weight of a trailer that the tow vehicle is capable of towing. The vehicle owner’s manual contains these specifications. Most automotive manufacturers and dealerships have towing specification guides with tow ratings and detailed information if extra equipment is needed to tow a trailer. While your vehicle may have certain tow ratings, remember you must have a matching hitch system that can handle the same specifications. To ensure safety, you may have to install extra towing equipment.

Manufacturers’ Tow Vehicle Ratings

Manufacturers’ tow vehicle ratings address tongue weight, as well as the individual, combined, and fully loaded weights at which a tow vehicle can safely tow a trailer. They also can be used to guide the selection of brake and hitching systems, as well as tow vehicle tires. Together with the hitch system specifications, these weight considerations will help you purchase a safe tow vehicle. In general, manufacturers provide tow ratings for the maximum

• Amount the tow vehicle may weigh when fully loaded, or Gross Vehicle Weight Rating (GVWR).
• Weight a vehicle can tow. This figure may vary depending on the vehicle’s equipment, such as a manual or automatic transmission and whether it is equipped with four-wheel drive. 
• Permissible combined weight of the tow vehicle, trailer, passengers, equipment, fuel, etc., that the vehicle can handle, or Gross Combination Weight Rating (GCWR).
• Weight a single axle can carry, or Gross Axle Weight Rating (GAWR). 

Measuring the Weight of a Trailer

Some manufacturers provide a “dry” or empty weight for trailers; however, to select a proper tow vehicle and hitching system, you must know how much your trailer weighs fully loaded. For example, if you are towing an open trailer that carries a boat or motorcycle, the fully loaded weight includes the weight of the trailer with the boat or motorcycle and any additional items being towed, such as fuel tanks, motors, and safety equipment.

Develop a realistic estimate of the total weight of your trailer. The time you spend doing this and getting properly equipped will save you time and money in preventing unexpected repairs to your tow vehicle and unanticipated breakdowns while on the road. In addition to speaking with dealers and other individuals who sell and use trailers, the best way to know the actual weight of your trailer is to weigh it at a public scale.

Manufacturers consider the loaded weight of a trailer when specifying tongue weight—the amount of the trailer’s weight that presses down on the trailer hitch. Too little tongue weight can cause the trailer to sway. Too much tongue weight can cause many problems, including not enough weight on the front wheels of the tow vehicle. When this occurs, the tow vehicle will be less responsive to steering. A weight-distributing hitch can remedy this problem by transferring weight to the front axle of the tow vehicle.

Manufacturers also establish the gross axle weight and provide a rating that denotes the maximum weight a single axle can carry. Knowing these weights will help you when it is time to load your trailer. Remember that the gross axle weight rating listed on the tow vehicle’s certification label must not be exceeded.