Towing and Rating Information
RATINGS are LIMITS established by the manufacturer, which are not to be exceeded. Ratings are based on structural strength, drive train strength, braking power, stability, controllability, and performance. Exceeding a rating invites unsafe conditions, potential damage, may void a warranty, may complicate an insurance claim, and in some cases, may violate a law.
Gross Vehicle Weight Rating- The MAXIMUM ALLOWABLE WEIGHT of the fully loaded vehicle, including liquids, passengers, cargo, and the tongue weight of any towed vehicle.
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. The GAWR assumes that the LOAD IS EQUAL ON EACH SIDE.
Gross Combination Weight Rating - The MAXIMUM ALLOWABLE COMBINED WEIGHT of the tow vehicle and the attached towed vehicle. GCWR assumes that 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.)
Gross Trailer Weight Rating -The MAXIMUM TOWED VEHICLE WEIGHT. Each component (receiver, drawbar, ball) 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, Tongue Load, Vertical Load Rating Different terms for the MAXIMUM VERTICAL LOAD that can be carried by the hitch.
TIRE RATINGS The MAXIMUM LOAD that a tire may carry is engraved on the sidewall, along with a corresponding COLD inflation pressure. A reduction in inflation pressure requires a reduction in load rating. Tire manufacturers publish charts that establish the load capacity at various inflation pressures
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)
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.
NCC: Net Carrying Capacity
(1996 RVIA Definition) The MAXIMUM WEIGHT of all personal belongings, food, fresh water, LP gas, tools, dealer installed accessories, etc., that can be carried by the RV.
Sleeping Capacity Weight Rating (2000 RVIA Definition) The manufacturers designated number of sleeping positions multiplied by 154 pounds (70 kilograms)
Cargo Carrying Capacity (2000 RVIA Definition) Equal to GVWR minus each of the following: UVW. full fresh potable) water weight (including water heater), full LP gas weight and SCWR.
Liquid Weights (pounds per gallon)
- Water: 8.3
- Gasoline: 5.6
- Diesel Fuel: 6.8
- Propane: 4.2
information above source: RV Safety and Education Foundation