RV Terms and Definitions 04

Awning – Retractable fabric shade mounted on the side of an RV.  Patio awnings – roof-like coverings that extend from the body of the camper –  are most commonly used, providing outside shade and some protection from the elements. Manual and power operated models are available.  RV screen rooms can be connected to the awning as can decorative awning lights. Other types of awnings are also used with RVs:

Note: This post is part of a continuing series created during the development of a glossary of RV Terms and Definitions for a new website.
  • Window awnings – shade and protection from elements over individual windows.
  • Slide-out awning; keeps off rain, snow and debris that can damage slide seals and migrate into the RV.
  • Entry door awning – shades the entrance and provides cover from the elements.
  • Outback awnings – canopy awnings that provide cover over toy hauler ramp as well and can be combined with a screen room.

ring-and-pinion gears Axle ratio – The ratio of the number of turns the drive shaft makes for each rotation of the rear tires as established by the ring-and-pinion gears in the rear axle.  The gears in the axle change the direction of drive rotation by 90° from the drive shaft to the axle shafts.  The gears also multiply the force provided by the drive shaft – the torque – providing a mechanical amplification.  Higher ratio values provide more torque per rotation of the drive shaft.  For example, a 4.10:1 means that the drive shaft must turn 4.1 turns to rotate the axle one revolution.  As well, if the drive shaft is delivering 100 lb-ft to the axle, the axle gears multiply that force by the same ratio (100 x 4.1 = 410 lb-ft). Lower gear ratios in the axle provide lower torque, but higher speed for the vehicle.  With a 3.08:1 ratio, the 100 lb-ft. torque of the shaft would deliver 308 lb-ft to the axle, a 25% reduction in torque.  A higher ratio gives more torque and less road speed for a given engine RPM, with a lower fuel economy.  For fuel economy, a lower axle ratio is best.

Axle weight – The axle weight or load of a vehicle is the total weight transmitted by all the wheels on a given axle to the surface beneath it. 5

campgroundBack in – a campground site with a single entrance, normally referred to as a back in site.  In the campground map segment on the right, sites 151 – 155 are designated as back in sites. Campgrounds with hookups at back in sites will normally have the hookups on or near the left side of the RV when the camper is backed in and picnic table and fire ring, if provided, on the right side.

5 Wikipedia – Axle load


RV Terms and Definitions 03

Arctic Pack – Original design or additions and/or modifications to an RV to enable its use in colder weather, which may include electrically heated tanks, heated mattress, added (or different) insulation, insulated and enclosed under-carriage, dual pane windows (perhaps even insulated gas-filled). May also be referred to as a “four season” or “all weather” package. Example: Lance 4 Seasons | All Weather Package.

Note: This post is part of a continuing series created during the development of a glossary of RV Terms and Definitions for a new website.

Articulation point – A pivot point or joint between two objects that allows relative movement between the two. With recreational vehicles, the articulation point is where the tow vehicle is connected to whatever it is towing. Normally, there is just one articulation point with RVs.  However, in a triple tow situation, where a boat or other small trailer is being towed behind a camping trailer, there will be two articulation points.  RV articulation points will normally be one of the following:

  • the fifth wheel hitch and the king pin on a fifth wheel trailer or
  • the ball and coupling on a bumper or receiver type hitch.

ATV – All-terrain vehicle; defined by the American National Standards Institute as a vehicle that travels on low-pressure tires, with a seat that is straddled by the operator, along with handlebars for steering control. While ATVs are designed to handle a wider variety of terrain than most vehicles, they are not truly able to traverse all types of terrain.4

Auxiliary batteries –  another term for the house batteries.

4 Wikipedia – All-terrain vehicle


RV Terms and Definitions 02

Amp, RV service – AC (alternating current) service in modern RVs are rated at either 30 amps or 50 amps. The ampere is unit of measure of electrical current.  A 30 amp service provides 12ov power to the camper through through a three wire power cord – black is hot, white is neutral and green is ground.  A four wire cord is used for 50 amp service – Black and red are hot, white is neutral, and green is ground.  The two hot wires supply two separate 120v legs in the RV. If the service is wired properly, the two hot wires are of different electrical phases and can be connected to supply 240 volt service.

30 amp receptacle
30 amp plug
50 amp recepticle
50 amp plug

Amp hour (Ah)– an ampere hour is the amount of charge in a battery that will allow one amp of current to flow for an hour.  A milliampere hour (mAh)  is 1,000th of an amp hour.  It is commonly used as a measure of charge in portable electronics batteries, such as a laptop computer or notebook, and provides an indication of how long it can operate without needing to be recharged.  A battery’s amp hour rating has little significance unless qualified by the design discharge period.  Cold cranking amps and reserve capacity ratings provide better information for battery selection.

Note: This post is part of a continuing series created during the development of a glossary of RV Terms and Definitions for a new website.

Anode rod – a sacrificial rod used mainly in metal hot water heaters.  When dissimilar metals and water combine an electrochemical process called galvanic corrosion occurs.  In this process one metal corrodes preferentially to another when both metals are in electrical contact and immersed in an electrolyte (the water in the heater). Galvanic rods are made of metal alloys that have a more active potential than the metal that would otherwise corrode, so the anode material is corroded – sacrificed –  instead.3

3Wikipedia – Galvanic Corrosion, Galvanic Anode


RV Terms and Definitions 01

12dC12-volt DC – A recreational vehicle’s low voltage, direct current system, powered by either a battery or an inverter when the RV is connected to electrical hookups or a generator.  Direct current means that the electrical current flows in one direction in the circuit.  12-volt DC powers components in the RV such as lights, water pump, LP gas furnace controls, generator starter, tank level indicators, and DC powered entertainment equipment.

Note: This post is part of a continuing series created during the development of a glossary of RV Terms and Definitions for a new website.

110AC120-volt AC – A recreational vehicle’s alternating current system, powered by way of electrical hookups in a campground – sometimes called shore power – or from a generator.  The voltage is the same as that normally found in homes.  Alternating current means that the electrical current changes direction in the circuit, normally 60 cycles every second (60 hertz). AC powers components in the RV such as the microwave, water heater in AC mode, refrigerator in AC mode, and AC electrical outlets.

Actual weight – The measured weight of the vehicle or it’s components.  Factory or sticker weights may be averages or estimates of weight. 1

Adjustable ball mount – used to attain proper height between a tow vehicle receiver and the coupler of the trailer or other vehicle that is being towed.  Normally used with weight distributing hitches,  the ball of the adjustable ball mount may be raised, lowered or tilted, for to attain the proper tongue weight and coupler height to level the trailer.

AGM – Absorbed Gas Mat, a type of battery using a glass mat to wick the electrolyte between the battery plates.  AGM batteries only have enough liquid electrolyte to keep the mat wet.  If the battery is broken, there is little or no liquid available to leak out.2

Airbag – term used to describe either factory installed air suspension systems on motorhomes or after market RV suspension enhancements.

1 Changin’ Gears – Understanding RV Weights
2 BatteryStuff.com – Gel vs AGM


Continued Progress. “New” page for Fifth Wheel RVs

The new page for Fifth Wheel RVs is finished and published, with applicable links being redirected to it.  The page explains fifth wheel campers and has links to 5th wheel manufacturers with listing of current models.

The explanation of fifth wheel campers includes the following (and more).

5th wheel hitch-smallIn RV applications, a fifth wheel hitch, mounted in the truck bed, is used to connect the truck and trailer.  Featuring a heavy duty pivoted plate with a guide slot and locking mechanism, the hitch is pinned in place to a set of rails anchored to the frame of the truck.  By pulling the anchoring pins, the hitch can be removed, leaving the bed available for maximum cargo capacity.

kingpinA downward facing plate on the fifth wheel camper has a large vertical pin called a kingpin, which slides into the guide slot on the lower plate and is locked into place by the 5th wheel hitch jaws.


Shadow trailers and a VW towing a “fifth wheel”

In researching upgrades and new material for this site, sometimes I come across the strangest things.

From 1970s ads:

shadow trailerFifth-Wheel Trailers usually hitch onto a pickup-truck cargo bed, but this new Shadow design from Harmon Industries, Warrensburg, Mo. tags onto a passenger-car rooftop. A removable steel plate, bolted to brackets along the roof gutters, take advantage of the roll-resistance built into modern roofs to firmly anchor the trailer hitch. Great maneuverability and easy tow handling are claimed for these rigs. Models of 18, 23, and 27 feet are being produced, and unfinished units are available for extra savings. Shell for the Shadow 18-foot Mini will start at about $1700; price is $6500 for the completed 27-footer fully equipped. Driver reports indicate the design is aerodynamically suitable and does not buffet at speed or in strong winds.


Class B RVs–new page

new page for Class B RVsContinuing with page additions and upgrades, the new page for Class B RVs is up.

I’m actually creating almost completely new pages for the each of the different types of RVs.  The old pages will automatically redirect visitors to the new page.

The new pages have a lot more content related to the topic.  For instance, the Class B Motorhomes page is actually a short article that describes what a Class B is and how it differs from the other motorhome classes.

The page also has links to current manufacturers of Class B RVs.

Kitchen and Table in Type B Motorhome

Example of kitchen and dining inside a Class B RV


New page for Class A RVs–Class A’s explained & links to current Class A builders.

imageMy new page for for Class A RVs is up. It is Class A Motorhomes explained – with links to current Class A manufacturers.

My goal with the new pages is to build a site that has good information that will be of use for people that are interested in RVs, whether they are new to RVing or old hands. I’m actually building the new site on a different URL, but as new pages are created, they are also published here.  This makes the content available now rather than waiting until the new site is complete.

The new site will include an extensive glossary of RV terms with pages of information that expand upon many of these terms.

For instance, the recent post, Tow Vehicle, was actually written for a page on the new site related to the glossary item, tow vehicle.

See  the Class A Motohomes page for more information.


1941 Flxible Clipper motor Home (Conversion)
(public domain image)

The Flxible Co. (originally the Flexible Sidecar Company) was an American manufacturer of motorcycle sidecars, funeral cars, ambulances, intercity coaches and transit buses, based in the U.S. state of Ohio. It was founded in 1913 and closed in 1996.


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