GCWR: What it means and where to find it

From an NTEA member What is the GCWR of a truck, and how is it determined? GCWR is the acronym for gross combination weight rating, but the meaning of the term can depend on who is asking the question. The root of the term originated from trailer towing, where the weight rating is a maximum value for the combination of a truck and trailer together. It represents the entire weight of all the connected vehicles at the ground, including the towing unit and trailer(s), equipment, driver, fuel and payload — everything that moves with the combination of vehicles. Chassis OEMs establish GCWR values as the weight limit the towing vehicle can safely move, while preserving performance. There are a number of factors and considerations involved in developing a GCWR, and standardized methods are defined in SAE J2807 for pickups and other light vehicles. There are some primary chassis components that contribute to the GCWR — the engine, transmission and drive axle ratio — which are typically listed with the associated ratings in OEM towing charts. Generally, a higher axle ratio will provide a higher GCWR for the same chassis model/powertrain. It should be noted that a maximum trailer weight will typically accompany these specifications because there is a limit to the amount of weight which can be attributed to the trailer — even if the combined weight of the loaded truck and trailer do not exceed the GCWR. However, the ratings of the towing equipment and other considerations must also be evaluated, as the GCWR and maximum trailer weight listings may not necessarily be achieved for a specific configuration. GCWR is also a criterion used by the Federal Motor Carrier Safety Administration (FMCSA) in determining if a driver requires a commercial driver’s license (CDL) for the combination being operated. FMCSA defines GCWR as “the greater of: (1) A value specified by the manufacturer of the power unit, if such value is displayed on the Federal Motor Vehicle Safety Standard (FMVSS) certification label required by the National Highway Traffic Safety Administration, or (2) The sum of the gross vehicle weight ratings (GVWRs) or the gross vehicle weights (GVWs) of the power unit and the towed unit(s), or any combination thereof, that produces the highest value. Exception: The GCWR of the power unit will not be used to define a commercial motor vehicle when the power unit is not towing another vehicle.” Note, the National Highway Traffic Safety Administration does not require GCWR as part of the information on vehicle certification labels, so unless a manufacturer were to include the value as extra information, motor carrier enforcement would tend to use the sum of the GVWRs as the GCWR during a roadside inspection. If the GCWR is 26,001 pounds or more, and the trailer being towed has a GVWR of 10,001 pounds or more, then the combination would be considered a commercial motor vehicle for CDL purposes (see CFR 49 PART 383—COMMERCIAL DRIVER’S LICENSE STANDARDS; REQUIREMENTS AND PENALTIES for more specifics). Another use of GCWR in the industry is for Federal Excise Tax (FET) as it applies to tractors. For vehicles the IRS would classify as a tractor, there is a two-part test that describes one to which the tax would not apply: (1) a GVW of 19,500 pounds or less and (2) a gross combined weight (GCW), in combination with a trailer or semi-trailer, of 33,000 pounds or less. The stated weight factors in the test do not specify the “rating” in the respective limits, but since the actual gross vehicle and gross combined weights, which vary with vehicle loading, should not exceed either of these ratings, the GVWR and the GCWR would serve as practical limits, and a tractor that has ratings within both of these limits should not be taxable. Each of these applications of GCWR traces back to the ratings by the manufacturers, so the OEM towing charts are a convenient source for these ratings. These are typically accessible through the respective body builder sites of the chassis manufacturers. Build configuration sheets that detail the components/features/specifications of a given chassis are another source for GCWR values. Truck dealers should have access to these records, as well as applications engineering teams within the respective OEMs. If you have additional questions, contact NTEA’s Technical Services Department (248-489-7090/info@ntea.com).

GCWR: What it means and where to find it

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