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Can Your Vehicle Carry the Load?

Reprint of an article by Carl A. Nelson

Perhaps one of the most ignored and misunderstood aspects of obtaining the proper vehicle for the job is determining the requirements the vehicle needs to fulfill. “Rightsizing” the vehicle will cut costs and downtime while increasing the comfort and efficiency of the employee.

A vehicle too small to meet your needs may result in an insufficient room, lower fuel mileage, excessive repairs and downtime, premature wear, and possible liability issues. Too large a vehicle may increase acquisition and operating costs, decrease mileage and maneuverability, and adversely affect employee comfort.

For these reasons, it is necessary to first identify your needs. The cargo type, weight, and size must be considered. What are the operating conditions–city, urban, rural? What are the temperature ranges and terrain? Will it need to tow, and if so, what type and size trailer?

Are there any corporate requirements, such as maintaining an image, external agreements, or special safety concerns? Do you have any special driver needs? All of these issues must be part of the equation when writing your specs. Before you can effectively determine your specs, however, you need to be aware of the following terms:

  • Curb Weight: The weight of the vehicle with all permanently mounted equipment and a maximum capacity of fuel, oil, and coolant.
  • GAWR: Gross Axle Weight Rating. The value specified by the manufacturer as the loaded weight of a single motor vehicle. It cannot exceed the sum of all GAWR’s.
  • GCWR: Gross Combination Weight Rating. The value specified by the manufacturer as the entire weight of vehicle, trailer(s), equipment, driver, fuel, and payload
  • Payload Capacity: The amount of weight the vehicle is rated to carry, computed by subtracting the curb weight from the GVWR.

Knowing Towing If towing is a part of your requirements, it is also necessary to be familiar with the following towing terminology:

Trailering Classes

  • Class I – Light Duty: 2,000-pound maximum weight, trailer, and cargo combined.
  • Class II – Medium Duty: 2,001 to 3,500-pound gross trailer weight, single axle, small to medium, length up to 18 feet.
  • Class III – Heavy Duty: 3,501 to 5,000-pound gross trailer weight, dual axle, or large single axle.
  • Class IV – Extra Heavy Duty: 5,001 to 10,000-pounds gross trailer weight, usually fifth wheel or gooseneck.

Hitch Types

  • Weight Carrying: Supports trailer tongue weight, used for Class I and II up to 300-pound tongue weight, 3,500-pound trailer weight.
  • Weight Distributing: Applies leverage between towing vehicle and trailer, distributing weight to all wheels.
  • Fifth Wheel: Typically Class IV or higher, mounting platform over rear axle improves sway control, makes long trailers more maneuverable.
  • Gooseneck Ball: Typically 2-5/16 ball mounted at bed level, improves sway control and maneuverability.
  • Tongue Weight must be included in payload calculations. Properly loaded tag-a-long trailers are usually 10 percent to 15 percent of loaded trailer weight. Fifth wheel and gooseneck trailers are typically about 25 percent of the loaded trailer weight.

TOWING CAUTION: You can maximize the vehicle manufacturer’s value for trailer size OR you can maximize the vehicle manufacturer’s value for payload. YOU CANNOT MAXIMIZE BOTH!

Defining the Categories

Several years ago, as part of a cost-cutting effort, AT&T recognized that many different sizes and types of vehicles were being used to support similar jobs nationwide. To analyze the differences, a Process Management Team was formed with representatives from each region.

The first step taken was to ask drivers to provide an inventory of the equipment and supplies carried on their vehicles. The responses were then compared, and the equipment and supplies were separated into broad categories, such as “Basics,” which included tools, personal items, driver weight, documents and reference materials, and communications equipment.

Some of the other categories were “Optional Equipment” (toppers, shelving, etc.), “Special Equipment” (winches, plows), “Occasional Allowances” (extra passenger, special project tools), and “Towing.”

The next step was to weigh the most common equipment in each category and determine an average weight. Using the results of this exercise, a “Weight Matrix” was devised listing the common items in each category and known weights.

Provisions were made to allow each driver to add his or her own weight for each item, and add additional items within each category. This provided the flexibility to accommodate regional variations as well as provide for customization. All weights could then be totaled and compared to the manufacturers’ specifications to ensure the vehicle ordered could meet the requirements.

Because at its’ implementation the matrix was required with each order, it was necessary that it be simple to understand and complete. the nationwide implementation resulted in considerable cost savings through lower downtime, fewer repairs, and standardization.

To illustrate this under real-world conditions, let us examine the following hypothetical scenario. The people and trip are fictitious, but the vehicle specs and weights are real.

It is important to understand that your weights may vary with your equipment. The principle, however, is the same whether you are looking at a Ford or a Freightliner, a Kia, or a Kenworth.

Ray’s Camping Trip

Ray has just purchased a shiny new Ford four-wheel-drive Super Cab short bed. He has a 5.4L V8, a 3.55 axle, and a 139″ wheelbase. The curb weight is 4,775 pounds with a payload of 1,725 pounds, for a GVWR of 6,500. The GCWR is 11,500, with a maximum trailer weight of 7,800.

He has invited his best buddies, George, Fred, and Al to go with him for a long weekend of camping, fishing, and relaxing. They will be towing Ray’s old fiberglass boat and trailer.

Ray has installed a fiberglass topper on his truck, which weighs in at 165 pounds. Additionally, he carries jumper cables (2 pounds), a toolbox (25), and a first aid kit (2). This has now reduced his available payload to 1,531 pounds (1,725 minus 165 minus 2 minus 25 minus 2 equals 1,531).

Ray weighs in at 190, George is 195, Fred is 185, and Al weighs 170. Subtracting this from the available remaining payload of 1,531 gives us 791 pounds of payload available (1,531 minus 190 minus 195 minus 185 minus 170 equals 791).

The four-person tent they are carrying weighs 23 pounds, four sleeping bags are another 20 pounds, the cookstove is 5 and two lanterns are an additional 4 pounds. Total is 52, leaving us with 739 available.

Now, let’s add in the cooler, with hot dogs, hamburgers, etc. (25), two cases of beer at 20 pounds each (light beer does NOT weigh less), coffee, snacks, canned goods (10), pots, pans, utensils, dishes (15), and these items add another 90 pounds of weight. Four folding chairs (16), personal items, i.e. shaving kit, change of clothes, jackets, etc. (15 pounds each), tackle box, boots, etc. (10 each), subtract another 116 pounds, bringing us down to 533 pounds remaining.

Ray’s older 20-foot fiberglass boat, with a galvanized trailer and big engine, weighs in at 5,250 pounds, fully outfitted. Since it is properly loaded, the tongue weight is 10 percent or 525 pounds. Subtract this tongue weight from the remaining payload of 533, and we are safe by 8 pounds. Or are we?

Pay Attention

As you can see by this example, neither the payload nor the trailer rating was exceeded, yet Ray was still overloaded. Without paying attention to what is put in/on the vehicle, it is very easy to become overloaded without even trying.

Adding to this illusion is the fact there is still plenty of space in the pickup bed for more items. Can the vehicle handle this? Perhaps, but stopping distances are increased, handling is severely affected, and the liability is unbelievable.

Try this little test on yourself. Take several common items and estimate their weights. Then, put them on a scale and compare their actual weights with your estimate. You will be amazed at the differences.

By becoming more aware of how quickly these can add up, you will not only save money but also put a much safer fleet on the road. What price can you put on that?