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hitchWiki - Our Towing Glossary

Here's our glossary of common terms used in the towing industry, we hope you find it helpful when trying to locate what you need for your next trip. 


the opposite of O.E.M.  This term refers to products or options which are installed AFTER a vehicle/motorhome/trailer has left the manufacturing plant.


all wheel drive.  When all 4 wheels on a vehicle are powered by the engine

axle lock

an add-on product which allows some vehicles to be towed on all 4 wheels behind a motorhome.  The axle lock allows the front wheels on the towed vehicle to turn freely, thus avoiding damage to the transmission.

Trailer Ball

trailer ball

the connection from the trailer hitch to the trailer.  Fits into the coupler on the trailer's frame. Here's a blog post explaining how to measure your trailer ball

Ball Mount


a removable platform that slides into the receiver opening of a trailer hitch and fastens with a pin and clip. The trailer ball is fastened to the flat part of the platform.  Also referred to as a 'drawbar'. Here's a blog post explaining how to measure your ballmount



steel bracket that connects the towed vehicle to the towbar.  All mounting brackets are bolted to the towed vehicle


when the towbar is difficult to detach because of excessive pressure

Brake Controllers

brake controller

interface between tow vehicle and the electric brakes on the trailer.  Can be inertia activated or based on time delay from activation of vehicle brakes.  Necessary for the use of electric trailer brakes.


a large box designed to slide into the box of a pickup truck.  Generally outfitted with beds / kitchen & used in overnight recreational outdoor activities.

camper jack

a lifting device used to load and unload a slide-in camper from a truck bed

camper anchor tiedown

a device to secure a slide-in camper to the bed of a pickup truck

camper anchor turnbuckle

a device used in connecting a slide-in camper to the bed of a pickup truck

Car Mounted Tow Bar

car mounted towbar

a towbar designed to be installed on the towed vehicle, perhaps behind a motorhome, truck or other vehicle.


the main structure of a vehicle, which all other parts attach regardless whether it is unibody or frame construction

Class 1 Trailer Hitch

class I trailer hitch

weight capacity of between 1k - 2.5k. fixed tongue (non-removeable ballmount) or flat 1-1/4" receiver opening. this hitch always includes the ballmount, pin & clip. will require a ball with a 3/4" shank.

Class 2 Trailer Hitch

class II trailer hitch

weight capacity of 3.5k only. 1-1/4" receiver opening only. The hitch always includes the ballmount, pin & clip. will require a ball with a 3/4" shank

Class 3 Trailer Hitch

class III trailer hitch

weight capacity of between 3.5k - 6k weight carrying, and 6k - 10k weight distributing. 2" receiver opening. this hitch does not include the ballmount or pin & clip. will require a ball with a 1" shank

Class 4 Trailer Hitch

class IV trailer hitch

weight capacity of 10k. 2" receiver opening. this hitch does not include the ballmount or pin & clip.

Class 5 Trailer Hitch

class V trailer hitch

weight capacity of 12k and up. 2" or 2-1/2" receiver opening. this hitch does not include the ballmount or pin & clip. requires a ball with a 1-1/4" shank


an electrical component that allows a 3-wire system towing vehicle (the vehicle has separate wires for brake lights and turn signals) to power the brake lights and turn signals on a 2-wire system trailer (the brake lights use the same light bulbs as the turn signals.)

trailer coupler

the forward most part of a trailer that envelopes and secures to the tow vehicle hitch ball.  Couplers can be removed and replaced on the trailer.  The coupler size must match the size of the trailer ball.

curb weight

the total weight of a vehicle or trailer when not loaded with either passengers or cargo


a wiring component which allows electrical current to flow in only one direction, thereby eliminating electrical feedback which could damage a vehicle's wiring fuses, or other.  Used on towed vehicles (behind motorhome) this device allows the towed vehicle to mimic the motorhome's brake and turn signal lights.

double eye spring

a spring with closed loops on both ends, with eye bushings inside the closed loops

double pivot

a feature available on 5th wheel hitches, whereby the head of the 5th wheel is designed to tilt both from side to side AND front to back.



dry hitch weight The amount of weight that will be transferred onto the towing vehicle before water, personal articles and supplies are installed in the trailer.
equalizer hitch

See Weight Distribution

Fifth Wheel Hitch

fifth wheel hitch

a hitch with a king pin receiver that mounts inside the bed of a pickup or flatbed truck.  The hitch connects with the king pin on the fifth wheel trailer.  Used for Heavy Duty towing applications.

Front Mount Hitch

front-mount hitch receiver

a steel tubular shaft designed to bolt to the FRONT of a towing vehicle.  Front receivers are application sensitive.


Front wheel drive.  When only the vehicle's front wheels are powered by the engine.

Gooseneck Hitch

gooseneck hitch

a hitch with a heavy duty trailer ball that mounts inside the bed of a pickup or flatbed truck.  The ball connects with a gooseneck coupler mounted on the front of a trailer. Here's a blog post describing what is a gooseneck hitch.


gross trailer weight.  Refers to a combination of the weight of the trailer and all of its contents.


gross vehicle weight.  The total weight of a vehicle or trailer when it is loaded.


gross vehicle weight rating - the manufacturer's suggested limit of a vehicle's weight towing capacity.  Can also be applied to towing equipment.  For example, a ballmount may have a GVWR of 6,000 lbs., which means it can safely tow 6,000 lbs.  The GVWR is always set by the manufacturer and is never to be exceeded.

Class 5 Trailer Hitch

trailer hitch

a steel fabrication designed to receive a towing accessory.  Available in a variety of applications, including 5th Wheel Hitches, gooseneck hitches, front mounted hitches, trailer hitches (rear mounted), etc.  In all cases, the selection of a proper hitch is vehicle application sensitive.

Inertia Brake Controllers

inertia brake controls

a law of physics describing the tendency of a body in straight line motion to stay in motion in a straight line unless acted on by an outside force.


when a trailer makes an extreme turn inward, towards the tow vehicle.  If the trailer body swings into contact with the tow vehicle it can damage / endanger the cargo, vehicle, driver, passenger or others on the road.

King Pin

king pin

a round steel shaft attached to the front of a fifth wheel trailer

lube pump

an add-on product which allows some vehicles to be towed on all 4 wheels behind a motorhome.  The lube pump ensures that all the necessary engine and transmission components on the towed vehicle are lubricated even though the vehicle is shut off and being towed behind the motorhome.

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

motorhome mounted towbar

a towbar designed to be stored on the back of the motorhome


Original equipment from Manufacturer.  This term refers to products or option which come FACTORY installed from the manufactoring plant, on either vehicles, motorhome, or trailers.


a trailer suspension setup where springs are mounted above the axle

power converter

electrical component used to power the trailer from the towing vehicle.  Power converters are compoatible (if wired correctly) with either a 2 or 3 wire system.  These converters draw a small amount of current through the vehicle circuit and do not interfere with the vehicle system diagnostics.  As opposed to a regular converter, with a power converter, all the additional power required to supply the trailer lights is supplied directly from the battery, virtually eliminating additional electrical draw on the vehicle's taillight circuits.

pintle hitch

a common heavy-duty coupling device 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, and agricultural equipment

Pintle Hook

pintle hook

the "jaw" portion of a pintle hitch which attaches to the tow vehicle.

Pintle Mount

pintle mount

an insert for a receiver hitch, having a shank with a flat plate to which a pintle hook gets bolted.


the receptacle (opening) part of a trailer hitch which accomodates inserts such as ballmounts, drawbars, pintle mounts, bike racks or other accessories.  Common receiver sizes are 1-1/4" and 2".

roll pan

a bumper style on pickup trucks where a fascia panel is used in place of a rear bumper.

safety cables

connect the towed vehicle to the motorhome.  They are a secondary safety device to hold the vehicles together in case one of the main towing components fails and there is a breakaway situation.

safety chains

connect the trailer to the towing vehicle.  They are a secondary safety device to hold the vehicles together in case one of the main towing components fails and there is a breakaway situation.  Safety chains are required in all States and Provinces.  When installed, they should be crossed under the tongue of the trailer so that the tongue will not drop to the road if it becomes separated from the hitch.  They should not be allowed to drag.

Trailer Spindle


provides the mounting area for the tires, wheels, and other "spinning" components on the trailer that make contact with the road. Here's a blog post further explaining what is a trailer spindle

Weight Distribution Shank

weight distribution shank

the piece that slides into the hitch and provides an attachment point for the equailizer head. A shank comes in different lengths, drops, and rises and allows you to adjust the height that your trailer sits at. Also called equalizer shank.

slider 5th wheel hitch

slider 5th wheel hitch

a feature available on some 5th wheel hitches, and practical for SHORTBOX pickup trucks (6' box.)  It allows the 5th wheel hitch to slide forward up to 10" to provide extra turning clearance when maneuvering the trailer.

slipper spring

a spring with a closed loop containing an eye bushing on one end, and the other end is flat, designed to ride or "slip" against a corresponding contact surface at its rear attachment point.

spring bar

the key component of a weight dirstribution system.  Spring bars work to distribute trailer tongue loads to the tow vehicle forward axle.

Surge Actuator Trailer Coupler

surge brake actuator

a self contained trailer brake system that is activated when the tow vehicle decelerates.  The momentum of the trailer pushes the surge brake housing forward.  This couses brake fluid to be forced into the wheel cylinders that apply the trailer brakes.  The entire process takes less than one second.

Sway Control

sway control

a device used to reduce or absorb the swaying movement of a trailer that can be caused by the wind, other passing vehicles on the road, or unbalanced cargo.  This device is used in conjunction with a weight distribution kit. There are two types of sway control: friction, and cam action.




Round Tube Hitch

round tube Hitch

a new style of hitches where the crossmember is made of a round steel tube, versus the old style square tubing.



a wiring component used to power the trailer lights from the towing vehicle.  This component server the same purpose as a converter / power converter / hardwire kit, but does not require splicing into the towing vehicle's wiring. Instead, it uses plugs installed on the vehicle from factory.  T-connectors are application sensitive.

tandem axle

two axles - commonly referred in trailers.

tongue weight

the downward force excerted on a rear mounted trailer hitch when the trailer is attached.  With a properly loaded trailer, the tongue weight is approximately 10% of the gross trailer weight.

Tow Bar


an accessory used in towing a vehicle behind a motorhome, which allows the towed vehicle to be transported with all four wheels on the ground.  A towbar inserts into the rear mounted trailer hitch on the motorhome and connects to the bolted aftermarket baseplate on the towed vehicle. There are a variety of brand and styles available, depending on budget.

tow dolly

a short, two-wheel trailer coupled to the motorhome for transporting a car or other towed vehicle with 2 of the vehicle's wheels off the ground.  Tow dollies are not applicable for certain rear-wheel-drive vehicles.

tow vehicle

the vehicle that pulls a trailer or towed vehicle.

towed vehicle

the vehicle being pulled behind a tow vehicle.

Trailer Hitch

trailer hitch

usually refers to the rear-mounted vehicle hitch.  Trailer hitches are divided up into different classes based on weight carrying capacities.  Trailer hitches are vehicle application sensitive.

transmission cooler

an add-on for the towing vehicle, which provides extra cooling for automatic transmission fluid.  This extends the life of the vehicle's transmission


a trailer suspension setup where springs are mounted below the axle

weight carrying capacity

the capacity of a hitch without any additional towing products to assist.  Also refered to as 'deadweight.'

weight distributing capacity

the capacity of a hitch when used in combination with a weight distribution (equalizer) system

Weight Distribution System

weight distribution hitch system

a optional system which can be added to most rear mounted trailer hitches.  The system 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 in some cases increases the trailer towing capacity (only if the hitch has a weight distributing capacity from factory.)


If we missed something you were looking for, just e-mail us and we'll make sure to add it!

-hitchweb Team-