GVWR (Gross Vehicle Weight Rating)
The maximum allowable weight of a fully loaded vehicle, including liquids, passengers, cargo, and the tongue weight of any towed vehicle.
GAWR (Gross Axle Weight Rating)
The maximum allowable weight each axle assembly is designed to carry, as measured at the tires, therefore including the weight of the axle assembly itself. GAWR is established by considering the rating of each of its components (tires, wheels, springs, axle), and rating the axle on its weakest link. In general the vehicle industry assumes that the load is equal on each side of the axle. For RVs this should not be assumed. The Recreaction Vehicle is a home on wheels with many compenents and floor plans designed for comfortable living which means there is a greater likelihood of side to side balance issues.
GCWR (Gross Combination Weight Rating)
The maximum allowable combined weight of a tow vehicle and an attached towed vehicle(s). GCWR assumes that both vehicles have functioning brakes, with exceptions in some cases for very light towed vehicles, normally less than 1,500 pounds. (Find GCWR - Towing Guides)
GTWR (Gross Trailer Weight Rating)
The maximum alowable towed vehicle weight for a hitch component. Each hitch component (receiver, drawbar, ball, etc) of a ball-type hitch has its own rating. Some ball-type hitches have separate ratings when used with a weight distributing system.
TWR/TLR/VLR Tongue Weight Rating, Tongue Load Rating, Vertical Load Rating, Pin weight Rating
Different terms for the maximum vertical load that can be carried by the hitch.
Tire Maximum Load
The maximum load or maximum load capacity of each tire is molded on the sidewall, along with a corresponding COLD inflation pressure. There may also be a 3 digit code which identifies the tires maximum load and is called the load index. A reduction in inflation pressure corresponds to a reduction in load carrying capacity. Tire manufacturers publish charts that establish the load capacity at various inflation pressures for each tire.
Weight and Load
These terms are generally used interchangeably. For the purposes of understanding RV applications, vehicles have weight, which impart loads to tires, axles, and hitches. Scale measurements taken when weighing are loads carried by the tires. These measured loads are used to calculate Gross Vehicle Weight (GVW), Gross Axle Weight (GAW), Gross Combination Weight (GCW), and hitch loads.
UVW (Unloaded Vehicle Weight - 1996 RVIA Definition - Definition changed in 2008 see below)
The weight of a vehicle when 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.
UVW (Unloaded Vehicle Weight - used after 2008
The weight of a vehicle when built at the factory with full fuel, engine(generator) oil and coolants and the weight of full propane containers. It does NOT include the weight of a full fresh water tank.
RV Trailer CCC (Cargo Carrying Capacity - 6/2008 NHTSA Definition Towable Only)
The weight of cargo that can be added to the RV Trailer before it exceeds the GVWR. The weight of cargo that can be added to the Motor Home before it exceeds the GVWR. Fresh water is considered cargo, so the weight of onboard water must be subracted from the CCC like any other cargo. The CCC is determined by the manufacture using the weight of the vehicle as it left the manufacturer facility including the weight of full propane containers.
Motor Home OCCC (Occupant and Cargo Carrying Capacity - 6/2008 NHTSA definition Motorized Only)
The weight of occupants/passengers and cargo that can be added to the Motor Home before it exceeds the GVWR. The weight of passengers or occupants in the RV must be subtracted from the OCCC just like any other cargo. Also, fresh water is considered cargo, so the weight of onboard water must be subracted from the OCCC like any other cargo. Lastly, tongue weight from a trailer is also considered cargo and must be subtracted from the OCCC like any other cargo. The OCCC is determined by the manufacturer using the weight of the vehicle as it left the manufacturing facility including the weight of full propane containers.
NCC (Net Carrying Capacity - 1996 RVIA Definition no longer used in vehicles after 2008)
The maximum weight of all personal belongings, food, fresh water, LP gas, tools, dealer installed accessories, etc., that can be carried by the RV.
SCWR (Sleeping Capacity Weight Rating - 2000 RVIA Definition no longer used in vehicles after 2008)
The manufacturers designated number of sleeping positions multiplied by 154 pounds (70 kilograms)
Liquid weights
  • Water: 8.3 lbs/gal
  • Diesel Fuel: 6.8 lbs/gal
  • Gasoline: 5.6 lbs/gal
  • Propane: 4.2 lbs/gal