COMMON TERMS, ACRONYMS AND DEFINITIONS
Brake Controller: A controller mounted inside the towing vehicle that allows electric trailer brakes to become automatically activated along with the braking of the tow vehicle, and can also be used to manually activate the trailer brakes.
Breakaway Switch: A safety device with the purpose of automatically activating the trailer brakes if the trailer becomes disconnected from the hitch while towing.
Bumper Pull Trailer: A Trailer that connects to a ball hitch that's attached to the tow vehicle's frame or bumper.
Coupler: A Trailer coupler is a device that connects a trailer to the hitch of the tow vehicle.
Curb Weight (Trailer): Curb weight is the empty weight of a trailer. This is the weight of the trailer with standard equipment and does not include the cargo.
Curb Weight (Vehicle): Curb weight is the empty weight of a towing vehicle (car, truck, motorhome, etc.) Included in this weight is the vehicle, the vehicle’s fluids, fuel and standard equipment, but not driver, other occupants or cargo.
Equalizer: A suspension component that allows transfer of a portion of the load on one axle to the adjacent axle(s) when traversing an uneven surface.
E-Z Lube Feature: A bearing lubrication system that consists of grease fitting installed into the end of each trailer spindle. A channel is provided to distribute grease to the inner bearing. A special double lip seal diverts the lubricant back toward the outboard bearing, thus lubricating both bearings without hub removal.
GCWR (Gross Combined Vehicle Weight Rating): GCWR is the maximum recommended gross combination weight. This includes the total weight of the tow vehicle (car, truck, etc.), its occupants and any cargo or content, plus the trailer and its cargo.
GTW (Gross Trailer Weight): GTW is the total weight of the trailer and is not a load limit or specification. This weight includes the trailer and all of the contents or cargo. GTW should never exceed the GTWR.
GTWR (Gross Trailer Weight Rating): GTWR is the total allowable or recommended trailer weight specified by a manufacturer when it is fully loaded. This includes the weight of the trailer and all of the contents or cargo.
GVW (Gross Vehicle Weight): The GVW is the total weight of the tow vehicle and is not a load limit or specification. This weight includes the vehicle, driver, passengers, cargo, contents, components and accessories. Some use this term interchangeably with GTW when referring to trailers.
GVWR (Gross Vehicle Weight Rating): GVWR is the total allowable or recommended vehicle weight specified by a manufacturer when it is fully loaded. Fully loaded includes the weight of the vehicle, driver, passengers, contents, components and accessories plus the tongue weight of a trailer if attached. Some trailer manufacturers use this term interchangeably with GTWR when referring to trailers.
GAWR (Gross Axle Weight Rating): The rated capacity of the vehicle running gear as defined by the lowest rated component in the system. Those components considered are the axle beam, the suspension system, the wheels or rims and the tires.
Hitch Class (Common): Maximum amount of weight a particular trailer hitch is engineered to hold.
Class I: Class I trailer hitches are designed to handle a gross trailer weight (GTW) of up to 2,000 lbs., with a maximum tongue weight of 200 lbs.
Class II: Class II trailer hitches are designed to handle a gross trailer weight (GTW) of up to 3,500 lbs., with a maximum tongue weight of 300 lbs.
Class III: Class III trailer hitches are designed to handle a gross trailer weight (GTW) of up to 5,000 lbs., with a maximum tongue weight of 500 lbs..
Class IV: Class IV trailerhitches are designed to handle a gross trailer weight (GTW) of up to 10,000 lbs., with a maximum tongue weight of 1,000 to 1,200 lbs.
Hub: The axle component that contains the bearings to which the wheel is attached. Hubs or plain hubs are used on axles without brakes.
LED Light (Light Emitting Diode): An LED is a solid-state, semiconductor device that has been specially designed to emit light. Unlike traditional, incandescent lights that use bulbs, LED lamps do not use delicate wire filaments that stretch, weaken and eventually fail.
Load Range: This information identifies the tire's load-carrying capabilities and its inflation limits Max.
Max. Load Single kg (lbs) at kPa (psi) Cold: This information indicates the maximum load and tire pressure when the tire is used as a single.
Nev-R-Lube: A bearing system that consists of pre-adjusted and permanently lubricated bearings in a cartridge. This system eliminates all bearing adjustment and servicing. This system cannot be utilized for axles that are subject to immersion in water.
PSI: The tire air pressure (Kilopascals / Pounds per Square Inch) measured with tires cold.
Payload: Payload is the number resulting from the subtraction of the curb weight from the GTWR or GVWR. This is the weight of the cargo in the trailer only, not including the weight of the tow vehicle or trailer.
Rim Size: The rim size and load range for your trailer.
Spindle: The end section of an axle to which the hubs are fitted.
Safety Chains: A set of chains mounted to the trailer frame, tongue or hitch. The chains should be crossed under the tongue of the trailer to "catch" the tongue of the trailer and keep it off the road in the event of accidental separation. They keep the trailer attached to the tow vehicle in case of hitch failure.
Shackle Link: A suspension component that connects the spring to the trailer frame. The double pivot action of the shackle links accommodates spring articulation and allows the spring to move freely.
Spring Hanger: A suspension component attached to the trailer frame to which is bolted either a spring eye, shackle link, or equalizer.
Tie Plate: A steel plate utilized in conjunction with u-bolts to clamp a leaf spring to an axle.
ST Tire: An "ST" is an indication that the tire is for trailer use.
Tire Size: The tire size and load range for your trailer.
Tow Rating: The tow rating is the manufacturer’s recommended towing capacity. This rating is often based on the GVWR plus other factors.
Tongue Weight: Trailer Tongue Weight is the downward weight or force exerted on the hitch ball of the tow vehicle. This is the amount of the trailer’s weight that is transferred to the tow vehicle from the trailer tongue.
U-Bolt: A “u-shaped” double ended bolt used to attach leaf springs to an axle.
VEHICLE TYPE: Model or style of trailer
VIN: The Vehicle Identification Number
Wheel Capacity: The load carrying ability of a wheel assembly at a specified inflation pressure.
Wheel Nut (or Bolt): Often called a “Lugnut”. A fastener used to attach wheels and/or rims to a trailer hub. Wheel nuts and bolts must be properly torqued to maintain the integrity of the entire wheel and hub system.