Truck specs that truly work

Trucks are designed to perform a job. For some, it’s to haul freight. For others, it’s to accomplish tasks such as utility work or landscaping. For these companies, it’s becoming increasingly important to have the proper vehicle for the job. A truck too big and you burn fuel. A truck too small, and the work takes twice as long. The wrong type or size of body on the truck, well, it’s then almost useless.

Because of that, Robert Johnson, director of fleet relations for the NTEA, has put together a list of the three most common mistakes (working out of order, doing what you’ve always done, and guessing) companies make when spec’ing their work trucks.

First, he wrote, is the decision to spec a chassis. In fact, the decision on which chassis to use should come much later in the process.

“Think about it,” he said. “An effective, productive work truck is designed to perform a specific job or series of jobs. Therefore, it makes sense to start the process by defining the job or jobs the truck will perform. From there, you can address the equipment and associated truck body needed to perform those tasks.”

Once these decisions are made, then you should look at the type of body and equipment needed. These will define the required payload, cab-to-axle chassis length, and the vehicle’s center of gravity.

“This information enables you to select an appropriately sized chassis and perform an accurate weight distribution and payload analysis to determine the appropriate chassis,” Johnson said.

Finish by choosing the powertrain most suited to your needs.

The second mistake to avoid is following a tried-and-true method. Just because your current vehicle is spec’d one way doesn’t mean it’s appropriate for the tasks ahead.

“For starters, the current vehicle may not have been optimized for the job it is doing,” Johnson said. “In such a case, the end users probably figured out how to make it work as well as they could, but that does not mean you shouldn’t improve the new unit. Even if the vehicle was properly spec’d at the time it was initially acquired, requirements change and new/ improved products are constantly being introduced.”

In particular, Johnson advised paying close attention to chassis selection. Because of changes  made by OEMs, your current Class 3 chassis may not have the same attributes as the new model from the same OEM.

“One of the challenges facing work truck designers is keeping up with these changes,” Johnson pointed out. “To some degree, you can accomplish this by reviewing new product literature and reading industry trade journals. However, nothing really beats seeing the equipment firsthand and talking directly to representatives of the companies developing this new equipment.”

The third mistake made is guessing. It’s not good enough to make a “best guess,” because that can lead to a vehicle not suited for the job at hand.

Johnson advised performing a detailed weight distribution analysis on the chassis you have chosen. This will ensure that optional axles, suspension components and frames are included if necessary to prevent vehicle overloading and equipment-mounting requirements have been met.

Then, shift your focus to the powertrain, electrical system, fuel tanks and cab requirements.

“In far too many cases, vocational truck designers make powertrain selections based on guesses instead of a careful analysis of horsepower and engine torque demands,” Johnson said. “Start by defining your performance criteria (road speed, starting gradeability, reserve gradeability, etc.) and then calculate your actual requirements. This will allow you to select the proper engine, transmission and axle ratio to ensure that the truck performs as required. The payoff in this process is a truck that has better fuel economy and lower maintenance costs.”

This also includes any trailers you will be hauling into the total vehicle weight.

 NTEA’s Work Truck Show, to be held March 5-7, 2014, in Indianapolis, IN, will include information on proper spec’ing.

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