RV Glossary

We've compiled an RV glossary for those wanting to master the terminology of the RV world.

Every industry has their own lingo and Rving is no different. There are hundreds of words describing RV issues, parts, and important information. Are you fluent in the RV language? See how many RV terms you are familiar with.


RV Glossary A

120 AC/12 DC/LP Gas

The power source that runs the RV refrigerators; 120 AC is 120-volt alternating current; 12 DC is 12-volt direct current; LP-gas. Some RV refrigerators can operate on multiple sources.

Adjustable Ball Mount

Allows the ball to be raised, lowered and tilted in small increments to fine tune the spring bar and compensate for tow vehicle "squat," which happens when the trailer coupler is lowered onto the ball.

Air Streaming

Towing an Air stream travel trailer.


Shock absorber at the front and rear axles of a motor home.

Anode Rod

Used in a water heater attracts corrosion causing particles in the water. Particles attack the anode rod instead of the metal tank. The anode rod should be inspected yearly and changed when reduced to 1/4 its original size. The rods are used in steel water heater tanks - an aluminum tank has an inner layer of anode metal to accomplish the same thing. Anode rods should not be installed in an aluminum tank.

Arctic Pack

Also spelled Arctic Pac and Arctic Pak, an optional kit to insulate RVs for winter camping.

Auxiliary Battery

Extra battery to run 12-volt equipment.

Axle Ratio

The final drive gear ratio created by the relationship between the ring and pinion gears and the rotation of the driveshaft. In a 4.10:1 axle ratio, for example, the driveshaft will rotate 4.1 times for each rotation of the axle shaft (wheel).

RV Glossary B

Back-Up Monitor

Video camera mounted on rear of motor home to assist the driver visually with backing up the motor home, with a monitor mounted in the driver's area of the cab. Also can monitor traffic behind the motor home and any vehicle in tow.

Ball Mount

The part of the hitch system that supports the hitch ball and connects it to the trailer coupler. Ball mounts are available in load-carrying and weight-distributing configurations.

Basement Model

Large storage areas underneath a raised RV chassis.

Black Water

Sewage from the toilet is flushed into a black water holding tank, generally located beneath the main floor of the RV.

Blue Boy/Blue-Boy

Plastic portable waste holding tank generally in a bright shade of blue.

Boon Docking

Parked in an RV without benefit of electricity, fresh water, and sewer utilities. Many people boon dock in WalMart parking lots.


The motor home living space on a class A, built from the chassis up.

Brake Actuator

Device mounted under the dash of a tow vehicle to control the braking of the trailer.

Brake Controller

A control unit mounted inside the vehicle that allows electric trailer brakes to become activated with the braking of the tow vehicle.

Breakaway Switch

Safety device that activates the trailer brakes in the event a trailer becomes accidentally disconnected while traveling.


British Thermal Unit ; A measurement of heat that is the quantity required raising the temperature of one pound of water 1 degree F. RV air-conditioners and furnaces are BTU-rated.


Term used to describe a variety of conditions; the level of RV when parked, referring to a bubble-leveler tool. Also describes a delaminating condition.

Bump Steer

term for the tendency of a wheel to steer as it moves upwards into jounce.

Bumper Mount Hitch

Bracket with a ball mounted to the bumper on tow vehicle. These hitches have very limited RV applications.

Bumper Pull

Slang term regarding the hitch or towing method for a conventional travel trailer or popup; receiver and ball-mount type hitch.


An RV area containing bunk beds instead of regular beds.

RV Glossary C


Overlapping top of a Class C motor home. Generally sleeping area in older models and storage or entertainment area in newer models.

Camber Wheel Alignment

Camber angle is the angle made by the wheel of an automobile; specifically, it is the angle between the vertical axis of the wheel and the vertical axis of the vehicle when viewed from the front or rear. It is used in the design of steering and suspension.

Camper Shell

Removable camper made to fit in the bed of a pickup truck.


A group of people traveling together.

Cassette Toilet

Toilet with a small holding tank that can be removed from outside the vehicle in order to empty it.

Castor Wheel Alignment

Steering wheel's tendency to return to center after the driver turns a corner.


Cargo Carrying Capacity, Maximum weight of everything you are carrying in your RV.

Chassis Battery

Battery in motor home for operating 12 volt components.

Class A Motor Home

Constructed on either a commercial truck chassis, a specially designed motor vehicle chassis, or a commercial bus chassis. The addition of slide-outs, first appearing in 1989, dramatically changed the industry, as they allow a wider room than would fit on the road.

Class B Motor Home

A commercial passenger bus that has been converted into an RV. Highly customized with luxury components, bus conversions are typically the largest motor homes available.

Class C Motor Home

Built on a truck chassis with an attached cab section, which is usually van based, but may also be pickup truck based or even large truck based. They are characterized by a distinctive cab-over profile, the "cab-over" containing a bed or an "entertainment" section. Also referred to as "mini-motor homes". In the UK, the cab-over is known as a Luton.


Another name for a motor home


Driver and front passenger area of a motorized RV.


The result of warm moisture-laden air contacting cold window glass. Keeping a roof vent open helps to reduce the humidity levels.


A device for changing 120-volt AC into 12-volt DC electrical power.


Trailer part that connects to the hitch ball.


Furniture arranged side to side rather than front to rear of the RV.

Curb Weight

RV with automotive fluids, fuel, oil and coolant, but no water in the holding tanks.


The side of the RV facing the curb when parked.

RV Glossary D


Also known as "knock" or "ping," this is a condition in which some of the unburned air/fuel in the combustion chamber explodes at the wrong time in the ignition cycle, increasing mechanical and thermal stress on the engine.

Diesel Puller

Motor home with a diesel engine in front.

Diesel Pusher

Motor home with a diesel engine in rear.


A booth like dining area in which the table may be lowered to convert into a bed.


A vehicle towed behind a motor home, sometimes with two wheels on a special trailer called a tow dolly, but often with all four wheels on the ground.

Dry Weight

Also called unloaded weight is the manufacturers estimate with no passengers, fuel, and water or supplies onboard.


Direct Spark Ignition; The method of igniting the main burner on a propane-fired appliance. The burner is lit with an electric spark and the flame is monitored by an electronic circuit board. This ignition system is used in refrigerators, furnaces and water heaters.

Dual Electrical System

RV equipped with lights, appliances which operate on 12-volt battery power when self-contained, and with a converter, on 110 AC current when in campgrounds or with an onboard generator.


A pickup truck, or light-duty tow vehicle, with four tires on one rear axle.

Ducted AC

Air conditioning supplied through a ducting system in the ceiling. This supplies cooling air at various vents located throughout the RV.

Ducted Heat

Warm air from the furnace supplied to various locations in the RV through a ducting system located in the floor.

Dump Station

Usually a concrete pad with an inlet opening connected to an underground sewage system at a campground or other facility offering dumping service to RVs.


Dry weight; The manufacturer's listing of the approximate weight of the RV with no supplies, water, fuel or passengers.

RV Glossary E

Engine Oil Cooler

A heat exchanger, similar to a small radiator, through which engine oil passes and is cooled by airflow.

Entry Level

Attractive price for first-time RV buyers of generally lower-cost RVs.

Equalizing Hitch

A hitch that utilizes spring bars that are placed under tension to distribute a portion of the trailer's hitch weight to the tow vehicle's front axle and the trailer's axles. The hitch is also known as a weight-distributing hitch.

RV Glossary F

Fan Switch

A normally open switch that closes at a preset temperature. It causes the furnace to run for a short time after the thermostat opens, allowing the furnace to cool down.

Fifth-Wheel Trailers

Designed to be coupled to a special hitch that is mounted over the rear axle in the bed of a pickup truck. These trailers can have one, two or three axles and are the largest type of trailer built. Because of their special hitch requirements, fifth-wheel trailers can only be towed by trucks or specialized vehicles prepared for fifth-wheel trailer compatibility.

Final Drive Ratio

The reduction ratio found in the gear set that is located farthest from the engine. This is the same as the axle ratio.


Other name for fifth wheel.


Family motor coach association

Frame-Mount Hitch

Class II and higher hitches are designed to be bolted to the vehicle frame or cross members. This type of hitch may have a permanent ball mount, or may have a square-tube receiver into which a removable hitch bar or shank is installed.

Fresh Water

Water suitable for human consumption.

Full Hookup

Term for campground accommodations offering water, sewer/septic and electricity; also refers to a RV with the abilities to use 'full-hookups'.


Living in one's RV all year long. RVers are known as full-timers.

Furnace Ignition Control Board

When powered, initiates gas valve opening and spark sequence which lasts approximately seven seconds. Newer boards are three try (i.e., will attempt to ignite three times at approximately 60 second intervals). Older models are single try.

RV Glossary G


The kitchen of an RV.

Garden Tub

Angled tub with wide edges around corners to bathroom items.

Gas Pusher

Slang for rear gasoline engine mounted chassis on motor home.


Dinette bench or sofa that converts to a sleeping area. Newer units have air mattresses in the sofas.


Gross Axle Weight Rating; Maximum weight per axle with weight distributed evenly on the vehicle.


Gross axle weight rating; Maximum to which the axle can be loaded, according to the manufacturer; includes all weight placed on all tires on a given axle.


Gross Combination Weight Rating; Maximum weight for the combination of tow vehicle, RV, passengers, water, fuel, propane, and everything on board.


Gross combination weight rating; Maximum allowable combined weight of the tow vehicle and the trailer, according to the vehicle manufacturer; includes the weight of vehicles plus all fuel, water, supplies and passengers.

Gear Vendor

Brand name for an auxiliary transmission designed to give the driver control of the vehicle's gear ratio and being able to split gears for peak performance and at the same time have an overdrive.


Gas or propane powered engine for generating 120-volt AC power when the RV is not connected to an electrical power source.


Abbreviation for generator set.


A colloquial name for fifth-wheel travel trailers.

Grey Water

Waste water from sinks, and shower. Generally held in a separate tank from black water.


Gross Trailer Weight; Gross trailer weight is the weight of the trailer fully loaded in its actual towing condition. GTW is measured by placing the fully loaded trailer on a vehicle scale. The entire weight of the trailer should be supported on the scale.


Gross Trailer Weight Rating; Maximum allowable weight of a trailer, fully loaded with cargo and fluids.


Gross Vehicle Weight Rating; The manufacturers maximum load weight, in pounds, allowed for the vehicle. This rating includes the weight of the vehicle plus fuel, water, propane, supplies and passengers and hitch weight. DOT regulates GVWR to a maximum or 26,000 lbs unless you have a CDL (Commercial Drivers License).

RV Glossary H


RV walls made of aluminum or other hard surface.

Heat Exchanger

A heat exchanger is a device that transfers heat from one source to another. For example, there is a heat exchanger in your furnace - the propane flame and combustion products are contained inside the heat exchanger that is sealed from the inside area. Inside air is blown over the surface of the exchanger, where it is warmed and the blown through the ducting system for room heating. The combustion gases are vented to the outside air.

Heat Strip

An electric heating element located in the air conditioning system with the warm air distributed by the air conditioner fan and ducting system. They are typically 1500 watt elements (about the same wattage as an electric hair dryer) and have limited function.

High Profile

A fifth-wheel trailer with a higher-than-normal front to allow more than 6 feet of standing room inside the raised area.


The fastening unit that joins a movable vehicle to the vehicle that pulls it.

Hitch Weight

Amount of a trailer's weight that rests on the tow vehicle; should be 10 to 15 percent with conventional trailers, 15 to 20 percent for fifth-wheels.

Holding Tanks

Holds the black (toilet) and gray (sink, shower, and lavatory) water. Their capacity determines how long an RV can be used without hookups.


Connections to a campground's facilities. The major types of hookups are electrical, water and sewer. Hookups may also include telephone and cable TV in some campgrounds. Full hookups refer to a combination of water, electricity and sewer.

House Battery

Battery or batteries in motor home for operating the 12-volt system within the motor home, separate from the chassis.


Abbreviation for "horse power".


Abbreviation for Holiday Rambler, a well-known RV manufacturer.

Hula Skirt

Term used for a type of dirt skirt accessory some RVers use on the back of their motor home to aid in the protection from debris thrown from their rear wheels to the vehicles directly behind them or being towed behind them. This dirt skirt is usually the length of the rear bumper and resembles a 'short' version of a Hawaiian 'hula-skirt', hence the term.

RV Glossary I

Igniter Electrode

Similar to a spark plug. There are two versions; a three probe (remote sense) and a two probe (local sense).


An inverter is a device that changes 12 volt battery power to 120 volt AC power. It is used when "boon docking" (camping without hookups) to power certain 120 VAC only devices like a microwave oven. The amount of available power depends on the storage capacity of the batteries and the wattage rating of the inverter.

Island Queen

A queen-sized bed with walking space on both sides.

RV Glossary J


90% angle obtained from turning/backing fifth wheel or travel trailer with tow vehicle. Jackknifing a short bed truck towing a fifth wheel without the use of a slider hitch or extended fifth wheel pin box can result in damage to the truck cab or breaking out the back window of the truck cab from the truck and fifth wheel "colliding".

RV Glossary K


Kampgrounds of America, a franchise chain of RV parks in North America that offers camping facilities to vacationers and overnighters.


Kilowatt; A measurement of electrical power; each kilowatt equals 1,000 watts.

RV Glossary L


A sandwich of structural frame members, wall paneling, insulation and exterior covering, adhesive-bonded under pressure and/or heat to form the RV's walls, floor and/or roof.


Positioning the RV in camp so it will be level, using ramps (also called levelers) placed under the wheels, built-in scissors jacks, or power leveling jacks.

Light Weight RV

RVs that are designed to be easily towed behind most Minivans, light-duty trucks and cars! The most common being a pop-up trailer. Also called Feather Weight in some models.

Limit Switch

A furnace safety switch that is normally closed but that opens if it gets to hot. When it opens, it turns off the power to the gas valve and igniter board.

Limited-Slip Differential

A differential that is designed with a mechanism that limits the speed and torque differences between its two outputs, ensuring that torque is distributed to both drive wheels, even when one is on a slippery surface.

Livability Packages

On rental RVs these items may be rented at an additional cost. Includes bed linens, pillows and blankets, bath towels, pots and pans, kitchen utensils, cutlery.

LP Gas

Propane; abbreviation for liquefied petroleum gas, which is a gas liquefied by compression, consisting of flammable hydrocarbons and obtained as a by-product from the refining of petroleum or natural gas. Also called bottled gas, LPG (liquid petroleum gas) and CPG (compressed petroleum gas).

RV Glossary M


Motor home

Minnie Winnie

Small Winnebago

Motor Coach

Term for motor home on "bus-type" chassis.

RV Glossary N


Abbreviation for National Automotive Dealer's Association.


Net Carrying Capacity; Maximum weight of all passengers (if applicable), personal belongings, food, fresh water, supplies -- derived by subtracting the UVW from the GVWR.

No Potable Water

Water not suitable for human consumption.

RV Glossary O



RV Glossary P

Park Model

Type of RV that is usually designed for permanent parking but is shorter in length than a traditional mobile home. All the amenities of a mobile home but not built for recreational travel.


People who use their RV for longer than normal vacation time but less than one year.

Patio Mat

Carpet or woven mat for use on ground outside of RV. Used whether or not a concrete patio pad is available where camping.

Payload Capacity

The maximum allowable weight that can be placed in or on a vehicle, including cargo, passengers, fluids and fifth-wheel or conventional hitch loads.


A small standby flame used to light the main burner of propane fired appliance when the thermostat calls for heat. Pilots can be used in furnaces, water heaters, refrigerators, ovens and stove tops.


Term for a RV campground "get-together", usually means "pitching-in" a covered dish or casserole.


Abbreviation for "pop-up" camper.


Term for room or area that 'pops-out' for additional living space in RV. This type of expanded living area was more common before the technology of slide-out rooms became popular and available.

Pop-Up Trailer

Folding camping trailer. Also known as a folding trailer, great for first timers due to its simplicity and relatively low cost.


A term used to define an up and down motion with a RV.

Primitive Camping

Also known as "dry camping", boon docking. Camping without the modern convenience of full-hookup facilities of city/well water, sewer/septic and electricity. Primitive campers rely on 'on-board' systems for these conveniences; generator, batteries, stored water, etc.


LPG or liquefied petroleum gas, used in RVs for heating, cooking and refrigeration. Also called bottle gas, for manner in which it is sold and stored.


Slang for front engine motor home. Term most often used to refer to front mounted diesel engine motor homes.


A campsite that allows the driver to pull into the site to park, then pull out the other side when leaving, without ever having to back up.


Slang for rear engine motor home. Term most often used to refer to diesel engine motor homes.

RV Glossary Q

RV Glossary R


The portion of a hitch that permits a hitch bar or shank to be inserted. The receiver may be either 11/2-, 15/8- or 2-inch square; the smallest being termed a mini-hitch.


Slang for "refrigerator". Refrigerators are often found in either a "two-way" or "three-way" operating mode. Two-way: Have a gas mode and an AC mode. Three-way: has a gas mode, AC mode, and 12v DC mode. The coolant used in RV refrigeration is ammonia. The two most common manufacturers of RV refrigerators are Norcold and Dometic.


Slang for an RV

Road Wander

Term used to describe a lack of ability to maintain the motor home in a straight, forward travel without constant back and forth motion of the steering wheel.

Roof Air Conditioning

Air conditioning unit mounted on the roof of an RV to cool the unit when it is parked. When moving, most RVs are cooled by air conditioning units which are components of the engine.


Recreational Vehicle; A motorized or tow able vehicle that combines transportation and temporary living accommodations for travel, recreation and camping. RVs come in all shape and sizes for any budget or need. They range from camping trailers costing a few thousand dollars to luxurious motor homes with prices well into six figures. RVs refer to multiple RV and RVers refer to their owners.


Recreational vehicle dealer's association


Recreational vehicle industry association.

RV Glossary S

Safety Chains

A set of chains that are attached to the trailer A-frame and must be connected to the tow vehicle while towing. Safety chains are intended to keep the trailer attached to the tow vehicle in the event of hitch failure, preventing the trailer from complete separation. They should be installed using an X-pattern, so the coupler is held off the road in the event of a separation.

Screen Room

Term for screen enclosure that attaches to the exterior of a RV for a "bug free" outside sitting area. Some screen rooms have a canvas type roof for rain protection as well.


An RV that needs no external connections to provide short-term cooking, bathing, and heating functions and could park overnight anywhere. Self-contained units can also hook up to facilities when at campgrounds.


Also called a hitch bar or stinger, the shank is a removable portion of the hitch system that carries the ball or adjustable ball mount, and slides into the receiver.

Shore Cord

The external electrical cord that connects the vehicle to a campground electrical hookup.

Shore Power

Electricity provided to the RV by an external source other than the RV battery.


Term for a type of camper that mounts on a truck bed, because often this type of camper "slides-in" to the truck bed.


Additional living space that "slides-out" either by hydraulics, electricity or manually, when the RV is setup for camping.


Slang for slider-hitch.


Referring to a sliding hitch used on short bed trucks for enabling them to tow fifth wheels, allowing them sufficient clearance to jack-knife the trailer.


Term for someone in a northern climate that heads "south" in winter months.


Telescoping side panels on an RV that can be raised or lowered, usually constructed of canvas or vinyl and mesh netting.

Spring Bar

Component parts of a weight-distributing hitch system, the spring bars are installed and tensioned in such a manner as to distribute a portion of the trailer's hitch weight to the front axle of the tow vehicle and to the axles of the trailer.


Also called a hitch bar or shank, the stinger is a removable portion of the hitch system that carries the ball or adjustable ball mount, and slides into the receiver.

Street Side

The part of the vehicle on the street side when parked.


Fishtailing action of the trailer caused by external forces that set the trailer's mass into a lateral (side-to-side) motion. The trailer's wheels serve as the axis or pivot point. Also known as "yaw."

Sway Control

Devices designed to damp the swaying action of a trailer, either through a friction system or a "cam action" system that slows and absorbs the pivotal articulating action between tow vehicle and trailer.

RV Glossary T

Tail Gunner

The end RV or vehicle in a caravan.

Tail Swing

Motor homes built on chassis with short wheelbases and long overhangs behind the rear axle are susceptible to tail swing when turning sharply. As the motor home moves in reverse or turns a corner, the extreme rear of the coach can move horizontally and strike objects nearby (typically road signs and walls). Drivers need to be aware of the amount of tail swing in order to prevent accidents.


Compacting from front to back and/or top to bottom to make the living unit smaller for towing and storage.


A thermocouple is a device that monitors the pilot flame of a pilot model propane appliance. If the pilot flame is extinguished the thermocouple causes the gas valve to shut off the flow of gas to both the pilot flame and the main burner.

Three-Way Refrigerator

Appliances that can operate on a 12-volt battery, propane, or 110-volt electrical power.


Term for room (generally in older RVs) that "tipped-out" for additional living space once RV was parked. Newer RVs mainly use 'slide-out' rooms.

Toad Or Dinghy

A vehicle towed behind a motor home, sometimes with two wheels on a special trailer called a tow dolly, but often with all four wheels on the ground.


Wheel alignment - Toe is the measure of whether the front of the wheels (looking down from the top) are closer (toe-in) or farther (toe-out) than the back of the wheels.

Tow Bar

A device used for connecting a toad/dinghy vehicle to the motor home when it's towed with all four wheels on the ground.

Tow Car

A car towed by an RV to be used as transportation when the RV is parked in a campground.

Tow Dolly

A low, wheeled frame with a platform used for carrying heavy objects. Motor home owners often use tow dollies to haul a car or SUV behind their RVs.

Tow Rating

The manufacturer's rating of the maximum weight limit that can safely be towed by a particular vehicle. Tow ratings are related to overall trailer weight, not trailer size, in most cases. However, some tow ratings impose limits as to frontal area of the trailer and overall length. The vehicle manufacturer according to several criteria, including engine size, transmission, axle ratio, brakes, chassis, cooling systems and other special equipment, determines tow ratings.


Term for fifth wheel, travel trailer or motor home with built-in interior cargo space for motorcycles, bikes, etc.

Trailer Brakes

Brakes that are built into the trailer axle systems and are activated either by electric impulse or by a surge mechanism. The overwhelming majority of RVs utilize electric trailer brakes that are actuated when the tow vehicle's brakes are operated, or when a brake controller is manually activated. Surge brakes utilize a mechanism that is positioned at the coupler that detects when the tow vehicle is slowing or stopping, and activates the trailer brakes via a hydraulic system (typically used on boats).

Transmission Cooler

A heat exchanger similar to a small radiator through which automatic transmission fluid passes and is cooled by airflow.

Travel Trailer

Also referred to as "conventional trailers" these types of trailers have an A-frame and coupler and are attached to a ball mount on the tow vehicle. Travel trailers are available with one, two or three axles.

Triple Towing

Term for three vehicles attached together. Usually a tow vehicle pulling a fifth wheel and the fifth wheel pulling a boat.


Tow vehicle


Tongue Weight; The amount of weight imposed on the hitch when the trailer is coupled. Also referred to as "hitch weight". Tongue weight for a travel trailer can be 10-15 percent of overall weight; fifth-wheel hitch weight is usually 18-20 percent of the overall weight.

RV Glossary U

Umbilical Cord

The wiring harness that connects the tow vehicle to the trailer, supplying electricity to the trailer's clearance and brake lights, electric brakes and a 12-volt DC power line to charge the trailer's batteries. An umbilical cord can also be the power cable that is used to connect to campground 120-volt AC electrical hookups.


The RV's under floor surface, which is protected by a weatherproofed material.


Uniform Tire Quality Grade Labeling; A program that is directed by the government to provide consumers with information about three characteristics of the tire: tread wear, traction and temperature. Following government prescribed test procedures, tire manufacturers perform their own evaluations for these characteristics. Each manufacturer then labels the tire, according to grade.


UNLOADED VEHICLE WEIGHT; Sometimes called the Dry Weight; it is the weight of the RV without adding fuel, water, propane, supplies and passengers. The manufacturers UVW will not include any dealer-installed options.

RV Glossary V

Van Conversion

A fully loaded van and the smallest of the fully enclosed motor homes. These are constructed on a van chassis with elevated roof lines but no modifications to the length or width of the original chassis. Gross vehicle weights are in the 6000 to 8000 range with heights of 7 to 8 feet and lengths of 17 to 19 feet.

RV Glossary W

Wagon Master

A leader, either hired or chosen, who guides a caravan of recreational vehicles on a trip. The wagon master usually makes advance reservations for campgrounds, shows, cruises, sightseeing and group meals.

Wally World

Slang for Wal-Mart.

Waste Water Tanks

The gray water tank holds the waste water from the sinks and showers. The black water tank holds the waste from the toilet.


People who own their RV's for weekend and vacation use.

Weight Carrying Hitch

Also known as a "dead-weight" hitch, this category includes any system that accepts the entire hitch weight of the trailer. In the strictest sense, even a weight-distributing hitch can act as a load-carrying hitch if the spring bars are not installed and placed under tension.

Weight Distributing Hitch

Also known as an "equalizing" hitch, this category includes hitch systems that utilize spring bars that can be placed under tension to distribute a portion of the trailer's hitch weight to the tow vehicle's front axle and the trailer's axles.


GAWR: Gross Axle Weight Rating. The maximum allowable weight each axle is designed to carry, as measured at the tires, therefore including the weight of the axle assembly itself. GAWR is established by considering the ratio of each of its components (tires, wheels, springs, and axle) and rating the axle on its weakest link. The GAWR assumes that the load is equal on each side. GCWR: Gross Combined Weight Rating. The maximum allowable combined weight of the tow vehicle and the attached towed vehicle. GCWR assumes both vehicles have functioning brakes, with exceptions in some cases for very light towed vehicles, normally less than 1,500 pounds. (Check your chassis manual or towing guide). GVWR: Gross Vehicle Weight Rating. The maximum allowable weight of the fully loaded vehicle, including liquids, passengers, cargo, and tongue weight of any towed vehicle. NCC: Net Carrying Capacity. The maximum weight of all personal belongings, occupants, food, fresh water, LP gas, tools, dealer installed accessories, etc., that can be carried by the RV. (Technically, the GVWR less the UVW equals the NCC.) Payload Capacity. The maximum allowed weight that can be in or on a vehicle, including all cargo and accessories, fuel freshwater, propane, passengers and hitch loads. UVW: Unloaded Vehicle Weight. The weight of a vehicle as built at the factory with full fuel, engine (generator) oil and coolants. It does not include cargo, fresh water, LP gas, occupants, or dealer installed accessories. Water (weight): 8.3 lbs. Per gallon LP gas (weight): 4.5 lbs. Per gallon driver (estimated weight): 200 lbs. Passenger (estimated weight): 120 lbs. Gasoline: weighs 6.3 pounds per gallon Diesel fuel: weighs 6.6 pounds per gallon Propane: weighs 4.25 pounds per gallon

Wet Weight

The weight of the vehicle with the fuel, freshwater and propane tanks full.


Distance between center lines of the primary axles of a vehicle. If a motor home includes a tag axle, the distance is measured from the front axle to the center point between the drive and tag axles.

Wide Body

Designs that stretch RVs from the traditional 96-inch width to 100 or 102 inches.


Nickname for Winnebago, a well-known RV manufacturer.


To prepare the RV for winter use or storage.

RV Glossary X

RV Glossary Y


Fishtailing action of the trailer caused by external forces that set the trailer's mass into a lateral (side-to-side) motion. The trailer's wheels serve as the axis or pivot point. Also known as "sway."

RV Glossary Z


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