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RV Glossary

Buying a new RV: RV Glossary

Ever wondered what a "Thermocouple" is? Well, we've got the answer!

Here you will find a list of common terms used in the RV Industry and their meanings.

115 VOLT SYSTEM: The main electrical source from the local municipality.

120 AC/12 DC/LP-gas: The power sources on which RV refrigerators operate; 120 AC is 120-volt alternating current (same as in houses); 12 DC is 12-volt direct current (same as in motor vehicles); LP-gas. Some RV refrigerators can operate on two of the three sources, others on all three.

Adjustable Ball Mount: Allows the ball to be raised, lowered and tilted in small increments to allow fine tuning of the spring bar setup and to compensate for tow vehicle "squat", which occurs after the trailer coupler is lowered onto the ball.

Anode Rod: When used in a water heater, an anode rod attracts corrosion causing products in the water. These products attack the anode rod instead of the metal tank itself. The anode rod should be inspected yearly and changed when it is reduced to about 1/4 of 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 Package: An RV that has been equipped with extra insulation and heat pads for holding tanks during winter time use.

Awning: The canvas or aluminum shade which is mounted on an RV. They may be automatic, in which case the awning is installed on a spring-loaded roll-up, or they may be manually propped up by a pole.

Axle Ratio: Ratio between pinion and ring gears in the differential that multiply torque provided by the engine. It describes the number of driveline revolutions required to turn the axle one time. With a 4.10:1 axle, the driveline turns 4.1 times for each full axle revolution. Higher numbers mean more torque and less road speed for a given engine speed; i.e., a 4.10:1 ratio provides more torque than a 3.73:1.

Back-Up Monitor: Video camera mounted on the rear of the motorhome to visually assist the driver with backing up the motorhome via a monitor mounted in the driver's compartment, or in a central area of the cab where it can be viewed by the driver from the driver's seat. These monitors are usually left in the ON position in order to also assist the driver with gauging the flow of traffic behind the motorhome, and in watching a towed vehicle.

Ball Height: Measurement from the ground to the center of the hitch ball or hitch ball coupling 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: The portion of the trailer which holds the hitch, ball, and the connecting device for the sway bars on a weight-distributing hitch, and the ball alone on a weight-carrying hitch.

Basement: Refers to a storage area accessible from the outside, usually from the door threshold area down.

Battery: The auxiliary battery installed in some RV units to provide 12 Volt lighting when the tow vehicle is not connected. When installed with an automatic charging solenoid, it charges through the tow vehicle alternator system, assuming the tow vehicle is wired with a charge line.

Black Water: Water from a toilet system held in an onboard holding tank until a means of disposal is available.

Boondocking: Camping without hookups. The term is also used among campers who like to enjoy nature at its fullest, regardless of the terrain, and avoid commercial campground fees.

Brake Controller: A device mounted under the dash of a towing vehicle to control the braking system of the trailer. The brake controller senses the amount of braking force of the tow vehicle and applies a proportional force to the trailer braking system.

Breakaway Switch: A safety device that activates the trailer brakes in the event a trailer becomes accidentally disconnected from its hitch while traveling.

British thermal unit (BTU) : A measurement of heat that is the quantity required to raise the temperature of one pound of water 1 degree F. RV air-conditioners and furnaces are BTU-rated.

Bubble Level: A device used to indicate the level of a trailer or motorhome. The level can be round, or cylindrical. A round level should be placed on a flat surface that is meant to be parallel to the ground. Cylindrical levels are placed in pairs, one at the front of the trailer, and one on the side, in order to indicate the state of level from side to side, and from front to back.

Bumper : The parts on a vehicle that protect the front and rear ends in the event of an accident.

Bumper-Mount Hitch : Available in two configuration: a bracket with a ball mounted to the bumper or a ball is attached to the bumper. These hitches have very limited RV applications.

Burner : The component in every LP gas appliance where the air and gas mixture ignites.

Castor (Wheel alignment): A steering wheel's tendency to return to dead center after the driver turns a corner.

Class A Motorhome: An RV with the living accommodations built on or as an integral part of a self-propelled motor vehicle. Models range from 24 to 40 feet long.

Class B Motorhome: Also known as a camping van conversion. These RVs are built within the dimensions of a van, but with a raised roof to provide additional headroom. Basic living accommodations inside are ideal for short vacations or weekend trips. Models usually range from 16 to 21 feet.

Class C Motorhome: An RV with the living accommodations built on a cutaway van chassis. A full-size bed in the "cabover" section allows for ample seating, galley and bathroom facilities in the coach. Also called a "mini-motorhome" or "mini." Lengths range from approximately 16 to 32 feet.

Cabover : The portion of a Class C motorhome which overhangs the driver and navigator seats.

Camber : Wheel Alignment - Number of degrees each wheel is off of vertical. Looking from the front, tops of wheels farther apart than bottoms means positive camber. As the load pushes the front end down, or the spring get weak, camber would go from positive to none to negative.

Caster: Wheel Alignment - The steering wheels' desire to return to center after you turn a corner.

Chassis : The frame of a vehicle. This is a main structure of a vehicle, which all other parts attach to regardless whether it is unibody or frame construction.

Chassis Electrical System : Brake lights, turning signals, and running lights powered by the RV's 12 volt system.

Clip : Used to retain pin in receiver style hitch.

City Water Hook-Up : A water inlet that is provided for campground hook-ups, which bypass the RV pump and the water tank entirely. The pressure of the local water supply pumps the water through the RV plumbing system when taps are opened.

Collar : The protective casing which partially surrounds the valve on an LP gas tank.

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

Converter: A device that converts 120 volt A/C (alternating current) to 12 volt DC (direct current). RV devices mostly run on 12 volt DC power that is supplied by the battery, which allows the RV to function independently. When "shore power" (an electrical supply) is available, the converter changes the voltage from 120 to 12 volt to supply the appliances and to recharge the battery.

Coupler : The part of the trailer that attaches to the ball of hitch.

Curb Weight or Net Weight: The weight of the RV as it is sitting on the lot, without the personal load you will be adding.

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

Deep Cell: A battery used exclusively by the living area of an RV, and not to start the vehicle. The more deep cycle batteries, the greater the longevity of your onboard power. The batteries are charged as you drive (if the tow vehicle is equipped with a charge line), when you are hooked up to 120 volt power (if the RV is equipped with a charger), by a generator, or by solar power.

Demand Water System: The system activated when you open a faucet in the RV. As water pressure in the pipe falls, a switch turns on a pump which operates until the depleted pressure is restored.

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

Diesel Puller: The term for motorhomes with the diesel engine mounted in the front of the vehicle. Also know simple as a Puller.

Diesel Pusher: Term used to describe the larger diesel powered motorhomes.

Dinghy: Towed vehicle. Also known as a "toad".

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.

Drop-Down : A ballmount with a drop in it to lower ball-height, to make the trailer ride parallel to the ground.

Dry Camping: Also known as boondocking, refers to camping without any hookups.

DSI (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.

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.

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.

Dually: 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 Outlet: The valve which controls the flow of effluent from the holding tanks.

Electric Brakes: The trailer brakes which are activated when the tow vehicle brakes are applied. An electric brake controller synchronizes the braking of the tow vehicle with that of the trailer. A hand control also allows the driver to apply trailer brakes independently.

Electrical System: There are generally at least two electrical systems in RVs, namely the 12 volt, and the 110 volt. The systems are controlled through a power converter which switches from the 12 volt travelling system to the 110 volt campsite system. Some vehicles have a generator which feeds the 110 volt system; others have auxiliary batteries which feed the 12 volt system.

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

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. This hitch is also known as a weight distributing hitch.

Dump Station: The hole in which RVers can unload their black and gray water using a flexible hose attached to their vehicles' holding tanks. The hole in which RVers can unload their black and gray water using a flexible hose attached to their vehicles' holding tanks.

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

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: A pull-behind travel-trailer that is constructed with a raised forward section that allows a bi-level floor plan.

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.

FMCA: Abbreviation for Family Motor Coach Association.

Folding Camping Trailers: A lightweight RV unit with sides, usually made of canvas, that collapse for towing and storage. They are also known as pop-up trailers. These are the smallest of the RVs that do not have an engine, and are easy to tow. The camping trailer combines the experience of tent camping with the comforts found in other RVs. When set up, they provide kitchen, dining and sleeping facilities for up to eight people.

Frame: The part of a vehicle which all other parts attach to. Frame usually refers to a non-unibody chassis.

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 Tank: One of two filling ports which feeds the fresh water system of the RV. One port has a hose connecting the RV to the water hookup; the other port is used as a funnel to fill the water tank for traveling.

Full Hookup: The ability to connect to all three of the campground's facilities: electric, water and sewer.

Full-Timers Or Full-Timing: The term used for people who live in their RV full time, or at least the vast majority of their time.

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.

Gas Pressure: LP gas pressure must be 11" of water column (6.25 oz per sq. in.), checking and adjusting requires a manometer.

Gaucho: The built-in couch in an RV that converts into a bed. It often conceals storage compartments.

Gear Vendor: Brand name for an auxiliary transmission designed to give the driver control of the vehicle's gear ratio. It enables splitting gears for peak performance, and at the same time, allows for an overdrive.

Generator: An engine powered device fueled by gasoline or diesel fuel, and sometimes propane, for generating 120-volt AC power.

Genset: Abbreviation for generator set.

Gray Water: Disposal water from sinks and shower. In some units, this is held in a holding tank separate from black water.

Gross Axle Weight Rating (GAWR): The manufacturers maximum load weight, in pounds, that can be placed on the axle. If an axle has a 3500-lb. GAWR and the RV has two axles (tandem axles), then the RV would have a Gross Vehicle Weight Rating (GVWR) of 7000 lbs.

Gross Combination Weight Rating (GCWR): Maximum allowable combined weight of the tow vehicle and the trailer, according to the vehicle manufacturer; includes the weight of both vehicles plus all fuel, water, supplies and passengers.

Gross Vehicle Weight Rating (gvwr): Maximum to which a vehicle can be loaded, according to the manufacturer; includes dry weight of the vehicle plus all fuel, water, supplies and passengers.

Gross Trailer Weight (GTW): 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.

Gooseneck: A Class 5 hitch that mounts a ball in the bed of a pickup truck to engage a coupler on a trailer.

Heat Exchanger: 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.

Hitch Ratings: Hitches are rated by the manufacturer according to the maximum amount of weight they are engineered to handle.

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.

Hitch Weight: The amount of a trailer's weight that rests on the tow vehicle's hitch. For travel trailers this weight should be 10-15 percent of the total weight of the trailer. For fifth wheels this weight should be 15-20 percent of the total weight of the trailer.

Holding tanks: Tanks that hold water. There are three different holding tanks on most RVs; fresh water tank, gray water tank and black water tank. The fresh water tank holds fresh water that can be stored for later use. The gray water tank holds the waste water from the sinks and showers. The black water tank holds the waste from the toilet.

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 motorhome for operating the 12-volt system within the motorhome separate from the chassis.

Hula Skirt: A skirt placed on the back bumper of a motorhome to stop debris that is thrown from the rear wheels from damaging vehicles behind the motorhome, either the vehicle you are towing or other vehicles behind the motorhome.

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

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

Kilowatt (kW): A measurement of electrical power; each kilowatt equals 1,000 watts.

Laminate : 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.

Leveling Jack: One of four lifting systems located at each corner of the RV to provide a solid and level foundation.

LP-gas : Liquefied petroleum gas; propane is one formulation and butane is the other. Propane fuels RV appliances, such as the stove and refrigerator.

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.

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 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: Items to equip a motorhome for daily living, which may be rented at a nominal cost, rather than brought from home. Includes bed linens, pillows and blankets, bath towels, pots and pans, kitchen utensils, cutlery.

Locking Pin: A hitch pin that locks with a key to prevent theft of a ball mount or other insert.

Luan: The 1/8" backing board for filon (the fibreglass sheeting used in RVs with fiberglass construction). Luan is the base that the filon (fibreglass) is glued onto.

Monitor Panel: A visual indicator of fluid levels within the storage tanks of the RV.

Net carrying capacity (NCC) or payload capacity: The amount of cargo, passenger and fluid weight that can be added to an RV without exceeding its gvwr. The NCC label in an RV may not include the weight of dealer- or factory-installed options already on the vehicle.

Part-Timers: The term used for people who use their RV more than usual (more than just a few weekend trips a year), but who still use it less than full time.

Park model: Type of RV that is usually designed to be parked permanently but is shorted that a traditional mobile home. All the amenities of a mobile home but not built for recreational travel.

Payload Capacity: The difference between the actual weight and the GVWR of the vehicle or trailer. Note that any options and accessories that you add are included in the payload capacity total of your RV unit.

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

Pop-Out: The term for a room in an RV that pops out for additional living space.

Popup Or Pop-Up: Another name for a folding camping trailer.

Pop-up Trailer: Also known as a folding trailer, great for first timers due to its simplicity and relatively low cost.

Portable Toilet: An RV toilet with a built-in water tank and holding tank. When the holding tank is full, it may be detached and taken to a dump station.

Pull-through: Term for camping space (whether in campground or not) that only requires the driver to "pull-through" or "drive-through" to access the camping spot, and upon leaving, you again just drive forward to leave or exit the camping space.

Propane or LPG (Liquefied Petroleum Gas): Propane or LP gas is used to fuel appliances in the RV, such as the stove, oven, water heater and refrigerator. Propane tanks are usually rated as pounds or gallons.

Regulator: The LP valve controlling the gas flow through all appliances, and maintaining the appropriate pressure in the LP gas system.

Relief Valve: A safety release in RV systems which opens when the temperature or pressure exceeds set limits. They are found on LP gas systems, and on pressurized water systems.

Rig: What many RVers call their units.

Roof Air Conditioning: An air conditioning unit that is mounted on the roof of an RV, to cool the RV when parked. When moving, most RVs are cooled by separate air conditioning units that are components of the engine, or they may be cooled by a roof top, if a proper size generator is installed.

Running Gear: A general term referring to the suspension system, axles, brakes, bearings, wheel and tires.

RVDA: Recreation Vehicle Dealers Association

RVIA: Recreational Vehicle Industry Association

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.

RV (Recreational Vehicle): A motorized or towable 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 motorhomes with prices well into six figures. RVs refer to multiple RV and RVers refer to their owners.

Safety Chains: A set of chains that are attached to the trailer A-frame and 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 (criss-crossed) so the coupler is held off the road in the event of a separation.

Screen Room: A screened enclosure that's attached to the exterior of an RV which provides a bug-free sitting area outside. Some screen rooms have a canvas type roof for rain protection as well.

Self Contained: An RV which needs no external electrical, drain or water hookup. Thus, it can park overnight anywhere. Of course, self-contained units can also hook up to facilities when at campgrounds.

Septic Tank: The black water holding tank.

Shore Power: Electricity provided by an external plug to external power source.

Slide-In: A term for a type of camper that mounts on a truck bed. Often, this type of camper slides into the truck bed.

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

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

Snowbird: An RVer who follows the sun south during the winter months.

Spring Bar: The part of a weight distributing hitch which does the lifting. A lever bar typically is made of spring steel.

Stabilizing Jack: A set of two or four are used to stabilize the RV once it is level.

Sway: Fishtailing action of the trailer caused by external forces that set the trailer's mass into a lateral motion. The trailer's wheels serve as the axis or pivot point.

Sway Bar: A device connected from the A-frame of the trailer to the hitchball platform of the tow vehicle in order to reduce sway.

Sway Control: Device 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.

Tail Swing: Motorhomes built on chassis with short wheelbases and long overhangs behind the rear axle are susceptible to tail swing when turning sharply. As the motorhome 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.

Tax Axle: A dead axle behind the drive axle that helps support the weight of the overhang and gives you a little more GVW capacity so you don't have to put the full load on the drive axle. Most tag axles are good for supporting 4,000-5,000 lbs.

Tent Trailer: A pull-behind trailer that folds up similarly to a tent. The upper portion is usually made of canvas.

Thermocouple: 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.

Toad or Dinghy: A vehicle towed behind a motorhome, sometimes with two wheels on a special trailer called a tow dolly, but often with all four wheels on the ground.

Tongue Weight (TW): 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.

Torsion Bars: The steel bars in equalizing hitch systems used to lever a portion of the weight of a trailer's hitch weight onto the forward axle of a tow vehicle.

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

Tow Rating: The manufacturer's rating of the maximum weight limit that can safely be towed by a particular vehicle.

Tow Vehicle: The vehicle that pulls a trailer.

Toy Hauler: Term for fifth wheels, travel trailers or motorhomes with built-in interior cargo space for motorcycles, bikes, etc.

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

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 positioned at the coupler that detects when the tow vehicle is slowing or stopping and activates the trailer brakes via a hydraulic system.

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.

Truck Trailer: An RV unit loaded onto, or affixed to, the bed or chassis of a pickup truck. Usually the tailgate is removed and the camper unit is attached to the truck with frame mounted tie-downs. Truck campers sleep two to six people.

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).

Underbelly: The RV's underfloor surface, which is protected by a weatherproofed material.

Unloaded Vehicle Weight (UVW) or Dry Weight: Weight of the vehicle without manufacturer's or dealer-installed options and before adding fuel, water or supplies.

Van Conversion: A fully loaded van and the smallest of the fully enclosed motorhomes. 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.

Weight Carrying: A towing situation whereby all of the tongue weight is carried directly on the rear of the tow vehicle and on the hitch.

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.

Wet weight: Weight of a vehicle with full fuel and freshwater tanks.

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

Wide Body: The term for an RV exceeding the normal eight feet wide. Wide bodies are usually 102" (8'6").

Yaw: Refers to the "fish-tailing" action of a 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".