*** Trailer and Towing Terms ***

Ball Mount

A ball mount - (aka: shank, stinger,hitch bar) Hitches come in two pieces. The receiver and the ball mount. The ball mount is slid into the receiver and secured by a lynch pin. Always be sure this lynch pin is pushed in all the way. Ball mounts can be load-carrying and weight-distributing configurations. An adjustable ball mount lets a hitch ball be raised up, lowered down and tilted to match up to the spring bar setup and to make up for tow vehicle "squat," which happens when the trailer coupler is mounted onto the ball.


-The Hitch Ball is the connection mating the hitch to the trailer.

Base Curb Weight

- BCW is the weight of a vehicle with a full tank of fuel but WITHOUT passengers, cargo, luggage or equipment.

Brake controller

- A controller mounted inside your towing vehicle that allows electric trailer brakes to become automatically activated along with the braking of the tow vehicle and can manually be used to activate the trailer brakes.

Breakaway switch

- A safety device with the purpose of automatically activating the trailer brakes if the trailer becomes disconnected from the hitch while towing.

Bumper pull

-Trailer that connects to a ball that's attached to the tow vehicle's frame or bumper. Also called "tag hitch" trailer.

Cargo Weight CW

- The sum weight of all the cargo added to the Base Curb Weight BCW, including the passengers and equipment.


- The trailer A-frame section that attaches to the hitch ball.

Curb Weight

- CW - The weight of the tow vehicle or trailer or both together as it is sitting. Without the load you will be adding.


- Usually a pickup truck with four tires on one rear axle.

Fifth-wheel trailers

- trailers designed to be mounted to a special hitch that is mounted over the rear axle in the bed of a truck. Fifth wheel trailers can be one, two or three axles and are the largest trailer built with the largest load capacity.

Frame-mount hitch

- Class II and higher hitches are bolted to the tow vehicle's frame or cross members. This type of hitch may be a permanent ball mount, or may have a square-tube receiver with a removable hitch bar or shank.

Gross Axle Weight -GAW

- The total weight supported by each axle, front or back. To determine this number, you weigh the vehicle and the trailer on a scale.

Gross Axle Weight Rating GAWR

Gross Combined Weight -GCW

- The actual weight of a vehicle and trailer combined. To get this weight, you have to weigh the vehicle and the trailer together on a scale.

Gross Combination Weight Rating- GCWR

- The maximum allowable weight of the tow vehicle and trailer, together.

Gross Trailer Weight GTW

- The weight of the trailer fully loaded.

Gross Vehicle Weight GVW

- the curb weight added to the cargo weight. The total weight of a vehicle when fully loaded.

Gross Vehicle Weight Rating -GVWR

- The maximum allowable weight of a vehicle, including passengers, cargo, fuel and hitch weight.

Hitch ratings

- Hitches are rated by the manufacturers for the the maximum amount of weight they are engineered to hold. There are six classes of hitches:
Class 1 - 1000 to 2500
GTW Class 2 - 3500 GTW
Class 2.5 - 4,000 GTW
Class 3 - 10,000 WD/6,000 GTW
Class 4 - 12,000 WD/8,000
GTW Class 5 - 14,000 WD/10,000 GTW

Hitch weight

- The amount of weight carried by the hitch when the trailer is coupled. Also referred to as tongue-weight.


-The maximum allowable weight of cargo and passengers that the vehicle is designed to carry.


- The portion of a hitch that accepts the ball mount or shank.

Safety chains

- A set of chains, usually permanently mounted to the trailers frame with a set of hooks that are either attached to specific places on the hitch or to the tow vehicles's subframe. The chains should be crossed under the tongue of the trailer and will "catch" the tongue of the trailer and keep it off the roadway in case of accidental separation. They keep the trailer attached to the tow vehicle in case of hitch failure.


- Also known as a hitch bar or stinger. A shank is the removable part of the hitch setup that has the ball or adjustable ball mount, and slides into the receiver.

Spring bar

- parts of a weight-distributing hitch setup. The spring bars are installed and tensioned to distribute some of the trailer's hitch weight to the front axle of the tow vehicle and the axles of the trailer.

Sway bar

- Device used to limit the swaying or fish-tailing of a trailer by a friction system or a cam action system.

Tongue weight

-The amount of the trailer's weight that is transferred to the tow vehicle through the trailer tongue, gooseneck or fifth wheel. Also referred to as "hitch weight".

Tow rating

- The manufacturer's rating of the maximum weight limit that can safely be towed by a particular vehicle. Ratings are for overall trailer weight, not trailer size. The ratings are determined by the vehicle manufacturer according to engine size, transmission, axle ratio, brakes, chassis, cooling systems and other special equipment.

Trailer brakes

- Brakes that are that are activated either electrically or by a surge mechanism. Electric trailer brakes that are activated when the tow vehicle's brakes are operated, or when a brake controller is manually operated. Surge brakes use a mechanism positioned near the coupler that "feels" when the tow vehicle is slowing or stopping and activates the trailer brakes using a hydraulic system.

Umbilical cord

- The electrical wiring harness attaching the tow vehicle to the trailer, for lights and electric brakes.

Weight carrying hitch

- a hitch that accepts the entire hitch weight of the trailer.

Weight distributing hitch

- an equalizing hitch-a hitch setup that uses spring bars under tension to distribute a portion of the trailer's hitch weight to the tow vehicle's front axle and the trailer's axles.

Weight Distribution- WD

- A Weight Distribution hitch is used to even the weight of the cargo between the front and rear wheels of the trailer for better steering, braking, and level towing.

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