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Combination › › › › › › › › › › › › › › › › › › › › › › › › › › ›
By Alex Stowe, NATM Technical Director
A tow vehicle’s operation will be impacted by towing a trailer. The larger the trailer and its cargo are in comparison to the tow vehicle, the greater the impact will be on the tow vehicle’s performance. Understanding the tow vehicle’s capabilities is just as important as choosing the right trailer. Vehicle manufacturers provide a “tow rating” in their owner’s manuals, which provides the maximum weight the tow vehicle can tow. The Gross Vehicle Weight Rating (GVWR) of the trailer should never exceed the tow rating of the tow vehicle, even if the trailer is not loaded to its maximum capacity.
Tow Rating
For specifics relating to tow rating, review the vehicle’s owner’s manual. The vehicle’s owner’s manual will have specific information on the vehicle’s tow rating, maximum loaded weight, maximum tongue weight and Gross Combination Weight Rating (GCWR). After determining this information, review the trailer’s owner’s manual and VIN tag to determine the GVWR for the trailer. Never use a tow vehicle with a max tow rating that is less than the GVWR of the trailer. Trailers 10,000 pounds GVWR or Less
On trailers that are 10,000 pounds GVWR or less, locate the trailer’s tire placard. This tire placard should be adjacent to, or near, the trailer’s VIN label on the front left side of the trailer. The placard will have a statement, “The weight of cargo should never exceed XXX kg or XXX lbs.” This number equals the trailer’s cargo load capacity. Determine the weight of the cargo being loaded onto the trailer and ensure the cargo load does not exceed the capacity listed on the trailer’s tire placard.
Trailers more than 10,000 pounds GVWR
Trailers more than 10,000 pounds GVWR are not required to have a tire placard. The empty weight of the trailer will need to be determined to assist with figuring out the trailer’s maximum towing capacity. The trailer can be taken to public scales or another weighing option to determine the weight of the empty trailer. Once the weight of the empty trailer has been determined, locate the trailer's VIN label and the trailer’s GVWR. Subtract the empty weight of the trailer from the trailer’s GVWR to determine the maximum available cargo capacity of the trailer.
It is vital to know the full weight of the cargo load that will be hauled to ensure the proper tow vehicle and trailer combination are being used.
Cars and Crossover SUVs can be used as towing vehicles, but their towing capacity will likely be lower than that of a truck or SUV. Here are some steps to assist with determining a tow vehicle’s cargo capacity.
First locate the statement, “The combined weight of occupants and cargo should never exceed XXX lbs,” on the vehicle’s placard. Next, determine the combined weight of the driver and all passengers who will be riding in the tow vehicle. Subtract the combined weight of the driver and passengers from the amount located on the vehicle’s placard. The resulting figure is the available amount of cargo capacity. For example, if the placard indicates the combined weight should not exceed 1,500 lbs and there will be five 150 lb passengers in the vehicle, the amount of available cargo capacity is 750 lbs (1,500-750 (weight of passengers 5 x 150) = 750 lbs). Then determine the combined weight of cargo loaded on the vehicle. The total of this weight may not safely exceed the available cargo capacity that was calculated in the previous step. If the tow vehicle will be towing a trailer, a portion of the cargo load from the trailer will be transferred to the tow vehicle. Consult the tow vehicle’s owner’s manual to determine what the vehicle manufacturer’s recommended hitch height is for the tow vehicle. The tow vehicle’s suspension must be able to support the trailer, and be able to keep the tow vehicle level to avoid creating negative stresses on the tow vehicle combination, which can make it harder to control.
The tow vehicle’s tire air pressure should be set to the tow vehicle and tire manufacturer’s recommendation. Proper tire air pressure will provide the smoothest riding experience and give the driver the most control over the trailer. Review the trailer owner’s manual to confirm the recommended air pressure for the trailer tires.
The tow vehicle must have mirrors on both sides, which will make it easier to see what is behind the tow vehicle. Avoid mirror placements that create blind spots with a trailer attached.
Each time a trailer is towed, ensure the proper hitch for the cargo load is used and that the trailer and tow vehicle are properly hitched. ■
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