Definitions of Common Terms

There are many terms related to hitches and towing that could bear some explaining. Here are some of the more common ones (in alphabetical order).

Base Curb Weight
Refers to the weight of a vehicle and a full tank of fuel, but does not include passengers, cargo or optional equipment.

Brake Controller
The interface between the tow vehicle and the electric trailer brakes. It is an electronic device that is needed for the use of electronic trailer brakes. There are inertia activated brake controllers and time delayed brake controllers.

Commercial Towing
This would be any vehicle and trailer combination exceeding 26,000 lbs. Gross Combined Weight (GCW).

Commercial Vehicle
Any vehicle that exceeds 10,000 lbs. Gross Vehicle Weight (GVW).

Coupler
The part of the trailer tongue that secures to the tow vehicle hitch ball.

Dual Cam Arm
This type hitch uses a damping mechanism that uses a “return to straight“ force derived from a cam system. This damping mechanism depends upon spring bar loading and there are reports that much better handling is achieved when the spring bar load ratings are closely matched to the actual hitch weight. This type of sway control starts to control sway before it happens rather than once it has already occurred.

Fifth Wheel Hitch
This is a specially designed hitch with a king pin receiver that mounts over or forward of the rear axle of the vehicle. Seen in pickup trucks often. The hitch connects with the king pin on the fifth wheel trailer.

Gooseneck Hitches
Similar to a fifth wheel hitch, but the difference is that the gooseneck uses a ball and coupler instead of a king pin and receiver. Typically used to tow a horse trailer.

Gross Axle Weight or GAW
The total weight supported by each axle (front or rear). To figure, take the loaded vehicle and trailer to a scale. With the trailer attached, place the front wheels of the vehicle on the scale to obtain the front GAW. To obtain the rear GAW, weigh the towing vehicle with the trailer attached, but with just the four wheels of the vehicle on the scale. The rear GAW is determined by subtracting the front GAW from that amount.

Gross Axle Weight Rating or GAWR
This would be the total weight that each axle is capable of carrying. The total load on each axle must not exceed its GAWR.

Gross Combined Weight or GCW
This is the actual total weight of the vehicle and the trailer combined, determined by weighing both together on a scale.

Gross Combined Weight Rating or GCWR
A combination of the vehicle weight, the loaded trailer, plus cargo and passengers.

Gross Towing Weight or GTW
The weight of the trailer plus all the cargo in it. This is measured by putting a fully loaded trailer on a scale.

Gross Vehicle Weight or GVW
The maximun allowable weight of the fully loaded vehicle.

Gross Vehicle Weight Rating or GVWR
This is the actual weight of the vehicle when it is fully loaded. It is the combination of the Base Curb Weight and the cargo weight.

Hitch Application
In the industry, hitches are commonly called "hitch applications". This would refer to the specific hitch that would fit your specific vehicle.

Hitch Ball
The part that the trailer coupler attaches to. It is usually attached to a ball mount, which is inserted into the receiver end of a hitch.

Hitch Head
Can also be called the Ball Mount. This bolts to the Shank on one end and has a Hitch Ball on the other end that fits into the trailer coupler.

Hitch Shank Hole
The diameter of the opening in the ball mount for the hitch ball shank to go through. The hitch ball shank diameter and the ball mounts shank hole diameter should match.

Hitch Tube Cover
The receiver end cap that fits over the 1-1/4" or 2" receiver end of a hitch. Designed to protect the end from the elements and to give the hitch a finished look. There are many designer or logo covers available to enhance the look of your vehicle.

Insert
An item that slides into a receiver of a hitch.

King Pin
This is the attachment at the end of a Fifth Wheel Trailer and the part that connects the trailer to the Fifth Wheel Hitch.

King Pin Funnel
The slanted sides of the groove on the Fifth Wheel Hitch that allows you to back your pickup into the groove and lock the connection between trailer and pickup.

King Pin Indicator
Simply put, this is an indication on the Fifth Wheel Hitch that the King Pin of the trailer has successfully seated and is locked into position.

Left Hand Adapter
This is used when sway control components block right hand sway control attachment.

Lunette Ring
This is a round metal ring that is used in place of a ball coupler on a trailer. The Lunette Ring attaches to a pintle hook on the towing vehicle.

Main Body Assembly
The section of the friction sway control unit that houses the actual sway controls.

Maximum Loaded Trailer Weight
This is the maximum allowable fully loaded weight of the trailer. It is obtained by subtracting the towing vehicle's GVW from its GCWR.

Payload
The GVWR minus the Base Curb Weight or the combined maximum allowable weight of cargo, occupants and optional equipment the vehcile is designed to carry.

Pin & Clip
The pin & clip are very important as they secure the receiver and the hitch or hitch accessory. The pin rests in the shank hole of the receiver and the clip fits over the head of the pin.

Pintle Hook
A special type of device which has a jaw which attaches to a tow vehicle.

Power Puck
On the Signature Series Fifth Wheel Hitch the mounting rails are under the bed. The Power Puck is where the Fifth Wheel Hitch attaches to the bed and they are bolted to the rails underneath the bed.

Pivot
In Fifth Wheel Hitches “side to side” pivot means it will pivot from pickup sidewall to sidewall. The fore to aft pivot means cab to tailgate pivoting.

Rail Kits
They are rails that are securely fastened to the truck bed and are needed to attach a fifth wheel hitch to your truck bed.

Receiver
The receptacle part of a trailer hitch which can take inserts such as ball mounts, bike racks and other accessories.

Round Bar
A type of Spring Bar Assembly where the steel bars are round in shape.

Safety Chains
Chains which are attached to the trailer tongue and has hooks on their free ends. They keep the trailer connected to the towing vehicle in the event the coupler or the hitch ball should come free.

Shank
The Shank bolts to the Ball Mount on one end and fits into the hitch receiver on the other end.

Slide Bar
This is the adjustment area of the friction sway control.

Slider
The slider is meant for short bed pickups and gives more turning clearance at low speeds and tight conditions. They come in both round tube and square tube models. The model from Curt Manufacturing is called a “Roller”.

Snap Up Brackets
This is a way to adjust the Spring Bar tension by changing links in the support chains.

Spring Bar
Part of a Weight-Distributing Hitch System. The Spring Bars work to distribute trailer tongue loads to the forward axle of the tow vehicle.

Sway
Trailer sway is caused by many factors, but the main cause is wind gusts (crosswinds) and sudden changes in direction of the towing vehicle. It can also be caused by passing traffic, improper loading, overloading, poor tire inflation and incorrect weight distribution.

Sway Control
A device similar to a shock absorber that will resist the swaying movement of a trailer tongue caused by wind and passing vehicles.

Tongue
This refers to the part of the trailer that extends forward from the trailer box and includes the coupler.

Tongue Weight or TW
This is the amount of the trailer's weight that presses down on the trailer hitch.

Tow Bar
A device attached to the front of a vehicle which allows it to be towed by another vehicle while riding on its own wheels.

Trunnion
The replaceable end of a square bar weight-distributing hitch which attaches to a ball mount.

Vertical Height Adjustment
On the base some Fifth Wheel Hitches have different holes allowing you to adjust how high the base is installed on the legs.