RV & Vehicle Weight Definitions
Over the years, there have been strides made in standardizing RV vehicle weight definitions, through the efforts of the Recreational Vehicles Industry Association (RVIA), RV Dealer’s Association (RVDA), RV Consumers Group (RVCG) and the RV Safety Education Foundation (RVSEF).
Manufacturers of trucks used to tow trailers fall outside of the realm of the RVIA, so you should always check specific manufacturer guides and manuals to understand vehicle weight definitions used.
Make sure you know what is included (or not included) in any numbers you get from a manufacturer, private owner, or dealer. It is very important to understand all weight and weight distribution in selecting and using your RV, tow vehicle and hitch mechanisms. Ratings cannot be changed as they are maximum weights determined by the manufacturer in the design of the vehicle.
While some of this effort has been aimed at making life easier for the RV consumer, a great deal of time has been spent by the RV industry to avoid having to comply with the safety standards of the federal highway regulations. While such compliance would be expensive, it would clearly improve the safety of travel in and by RV.
Gross Vehicle Weight Rating represents the total weight the entire RV can weigh, when weighed on a scale. Fully loaded the RV cannot exceed this number or it is overweight and undue stress will be put on the chassis, engine, tires, etc. Carrying capacity is not necessarily related to the GVWR. Some RVs have heavy fittings like hardwood cabinetry, ceramic tile, and other heavy interior items built in so that there isn't much room for any cargo carrying ability while some lighter RVs may have plenty of cargo capacity simply because of construction differences.
GCWR (Gross Combination Weight Rating) is 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 (usually under than 1,500#). Check your chassis manual or manufacturer towing guide. This weight limit applies to both motorhomes and to trucks towing trailers.
UVW (Unloaded Vehicle Weight) is the weight of the unit as built at the factory with full fuel tanks, engine oil and coolants. The UVW does not include cargo, fresh water, LP gas, occupants or dealer-installed accessories. All too frequently it is based upon design and not the actual weight of the RV as it left the assembly line.
NCC (Net Carrying Capacity), used from 1996 – 2000, is the maximum weight of all personal belongings food, fresh water, LP gas, tools, dealer-installed accessories and other items that can be carried by the unit.
CCC (Cargo Carrying Capacity), used since 2000, means GVWR minus the following: UVW with full potable water system (including water heater), full propane tank, and SCWR. Optional equipment not included in the UVW will lower the Cargo Carrying Capacity.
SCWR (Sleeping Capacity Weight Rating) adopted by RIVA in 2000, is the manufacturer–designated number of sleeping positions multiplied by 1543 (70 kg).
GAW (Gross Axle Weight) is the weight of a fully loaded vehicle that is supported by a single axle, obtained by weighing the vehicle on a scale. There should be one of these for each axle of the RV. For motorhomes the front will be higher than the rear and if there is a tag axle it will also have a rating. For most towed RVs the axle ratings are all equal.
Dry Weight/Wet Weight/Curb Weight: Dry Weight is normally used to refer to the empty weight of a vehicle or trailer. Curb Weight or Wet Weight definitions generally refer to the vehicle weight including standard equipment, oil, lubricants and a full tank of fuel. It does not include optional contents or other optional equipment, the weight of driver, passengers or cargo. Sometimes, but not always, it includes fresh water and LP.
OCCC (Occupant and Cargo Carrying Capacity) (for Motorized RVs only): This figure lists the maximum allowable weight of all occupants (including the driver), plus the weight of all food, tools, full fresh water tanks, full LP-Gas tanks and personal belongings. The maximum allowable weight of passengers is based on the number of seat belted positions in the motorized RV. The regulation also states that the “tongue weight of towed trailer counts as cargo.”
Payload: Payload capacities generally are computed by subtracting the curb weight of the vehicle from its specified Gross Vehicle Weight Rating (GVWR). The addition of any optional equipment or passengers adds to the vehicle weight and subtracts from the allowable payload.
Summary: The sad fact is that to be safe you can only rely upon the weights which are design limits (GVWR, GCWR, etc.) and those which you get from a certified scale or scale ticket for the vehicle in question.
Last Updated on Sunday, 10 March 2013 15:37