common towing terms
AWD - All-wheel drive.
Ball height - Measurement from the ground to the center of the hitch ball or hitch ball coupling (trailer) when parked on a flat surface and parallel to the ground. Used to determine the amount of drop or rise needed in the ball mount to make the trailer ride parallel to the ground when being towed.
Ball mount - A removable hitch ball platform that slides into the receiver of a hitch and fastens with a pin and clip. Different ball mounts can be used to raise or lower the height of the ball to allow for level trailer towing.
Bolt-on hitch (permanent undercar hitch) - A device which attaches directly to the tow vehicle providing the connection between the tow vehicle and the trailer. A fixed tongue hitch includes the ball platform, while a receiver style hitch has a receptacle (typically 1-1/4" or 2") for inserting special ball mounts or bike racks.
Brake controller - Interface between tow vehicle and electric trailer brakes. Can be inertia activated or based on time delay from activation of vehicle brakes. Typically in the tow vehicle's driving compartment with electrical line running to the trailer wiring connector. Most require the user to adjust brake gain to compensate for varying trailer load. Necessary for the use of electric trailer brakes.
Bumper - The parts on a vehicle that protect the front and rear ends in the event of an accident. Some trucks and SUVs have a tow bumper (or step bumper) for attaching a hitch ball for towing.
Class 1 (Class I) hitch - Trailer hitch with capacity of up to 2,000 lbs gross trailer weight and 200 lbs tongue weight.
Class 2 (Class II) hitch - Trailer hitch with weight-carrying rating of up to 3,500 lbs gross trailer weight and 300/350 lbs tongue weight.
Class 3 (Class III) hitch - Trailer hitch with weight carrying rating of up to 5,000 lbs gross trailer weight and 500 lbs tongue weight. Also sometimes used to refer to a hitch with any 2" receiver, regardless of rating.
Class 4 (Class IV) hitch - Trailer hitch with weight carrying rating of up to 10,000 lbs gross trailer weight and 1,000 - 1,200 lbs tongue weight. Although many times any hitch with a capacity greater than 5,000 lbs gross weight is referred to as a Class 4.
Converter - Converts 3-wire tow vehicle electrical systems to 2-wire systems by integrating the stop and turn signal circuits as is common in trailer wiring.
Custom hitch - A hitch that is designed for a particular year, make and model of vehicle. Because these hitches are made for a specific vehicle, the best possible appearance can be achieved.
Coupler - The part of the trailer tongue holding the hitch ball used to secure the trailer to the tow vehicle.
Curb weight - The empty weight of a vehicle full of fuel and all fluids. Curb weight does not include passengers or payload.
Drawbar - A removable coupling platform that slides into a hitch receiver and fastens with a pin and clip, or the "tongue" portion of a fixed-tongue hitch. The term drawbar is sometimes used to distinguish a ball mount with a solid ball shank or a coupling configuration different than a hitch ball (such as a pintle hook).
Fifth wheel hitch - A Class 5 hitch that mounts in the bed of pickup truck which uses a plate in the bed of the truck (similiar to a semi-tractor) and a pin on the trailer.
Fixed tongue hitch - A hitch with an integral ball platform (tongue) that cannot be removed.
FWD - Front-wheel drive
Gooseneck - A Class 5 hitch that mounts a ball in the bed of a pickup truck (either 2-5/16" or 3" in diameter) to engage a coupler on a trailer. Not to be confused with a fifth wheel.
Gross Towing Weight (GTW) - This is the weight of the trailer fully packed. This is measured by putting a fully loaded trailer on a scale.
Gross combined vehicle weight (GCVW) - Total combined weight of the two coupled vehicles, including all passengers and payload.
Gross vehicle weight (GVW) - The total weight of a vehicle including all of its contents and passengers.
Gross vehicle weight rating (GVWR) - The weight specified by a manufacturer as the recommended maximum weight of a vehicle when fully loaded
Hitch - A device which attaches directly to a tow vehicle providing the connection between the tow vehicle and the trailer. Hitch installations are most often considered permanent.
Hitch ball - The ball-shaped attachment to a hitch onto which a trailer coupler is attached.
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.
Jackknife - An extreme turning manuever that risks damage to the tow vehicle and the trailer when the trailer tongue or body swings into the contact with the tow vehicle. Jackknife accidents usually occur while backing up.
Locking pin - A hitch pin that locks with a key to prevent theft of a ball mount or other insert.
Lunette eye - A round metal ring used in place of a ball coupler on a trailer. It attaches to a pintle hook on the towing vehicle.
Payload - The transported load. Freight, excluding the weight of the trailer or tow vehicle.
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.
Pin - Used to fasten any insert (ball mount, bike rack) into a receiver hitch. Available in standard and locking configurations.
Pintle hitch - A common heavy-duty coupling type which utilizes a pintle hook attached to a tow vehicle to pull a trailer having a lunette eye. Pintle hitches are commonly used on military, construction, industrial and agricultural equipment.
Pintle hook - The "jaw" portion of a pintle hitch which attaches to the tow vehicle.
Pintle mount - An insert for a receiver hitch, having a shank with a flat plate to bolt a pintlehook to. These mounts are typically adjustable for vertical height.
Plug - The connector used to connect trailer wiring to a tow vehicle.
Receiver - The receptacle part of a trailer hitch which accommodates inserts such as ball mounts, drawbars or accessory carriers. Common receiver sizes are 1-1/4" and 2".
Receiver cover - A temporary receiver end-cap insertable into a 1-1/4" or 2" hitch receiver. Designed to protect from the elements. Also used to mask or enhance the look of the hitch when not in use.
Receiver style hitch - Any hitch with a receptacle (typically 1-1/4" or 2") which accommodates inserts such as drawbars, ball mounts, or bike racks.
Safety Chains - Chains are attached to the trailer tongue and have 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.
SUV - Sport utility vehicle
Sway control device - A device similiar to a shock absorber which resists swaying movement of a trailer tongue sometimes caused by passing vehicles and wind.
Tandem axle - Two axles (four wheels).
Tongue - The part of the trailer which extends forward from the trailer box and includes the coupler.
Tongue Weight (TW) - The downward force exerted on the ball by the trailer coupler. Generally tongue weight should not be more than 10% of the gross trailer weight.
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.
Tow vehicle (towing vehicle) - The vehicle that pulls a trailer or towed vehicle.
Weight distribution system - A hitch system built around a receiver hitch, which includes supplemental equipment such as spring bars that work to distribute trailer tongue loads to the trailer axle(s) and the tow vehicle front axle. Use of weight distribution system enhances handling and braking and increases trailer towing capacity beyond what is recommended when a weight-carrying hitch is used.