Spec'ing Work Trucks

Though usually smaller and lighter than freight haulers, these vehicles can be complex and are made for many applications.

February 2014, - Cover Story

by Tom Berg, Senior Editor - Also by this author

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This 18-foot steel dump body has a combination double-acting and high-lift tailgate that works well with loads like large rocks, and a forklift can push palletized cargo aboard. The gate is operated by a pair of air cylinders, one on each side, so the driver can stay in the cab.
This 18-foot steel dump body has a combination double-acting and high-lift tailgate that works well with loads like large rocks, and a forklift can push palletized cargo aboard. The gate is operated by a pair of air cylinders, one on each side, so the driver can stay in the cab.

Although work trucks are typically smaller and lighter than Class 8 freight haulers, often they are more complex and take more work to design and assemble.

Work trucks are built to carry tools, parts, expendable supplies and other equipment that its driver or crew needs to accomplish a job. Examples include public utility line construction and repair, tire and mechanical service, drilling, landscaping, plumbing and so on. They may need cabinets, shelves, plow mounts, and so on, and electrical and hydraulic power sources.

Upfitters install the bodies and equipment for specific types of work. Some body manufacturers do their own upfitting. Distributors handle body and equipment products from a number of manufacturers, sometimes entering into partnerships with them.

Upfitters by federal law are the final manufacturers of work trucks and must certify them for safety. So they must know all applicable federal motor vehicle safety standards, not to mention state weight laws and other regs that affect truck configurations.

An upfitter may need to comply with as many as 10 federal standards, from lighting and braking to windshields and fuel system integrity, according to Steve Strine, technical services manager at the National Truck Equipment Association. NTEA’s approximately 1,600 member companies manufacture, distribute, install, sell and repair commercial trucks, truck bodies and equipment, trailers and accessories.

There are many kinds of bodies, but to keep this article manageable, we focused on two basic types: utility and service (whose cabinets and compartments are accessible from outside), and dump (which are often paired with cabinets, tool boxes and snow removal equipment). Both these types generally are mounted on a wide range of truck chassis weight classes.

Workers at Reading Group install a utility body on a Ford SuperDuty chassis. Upfitters must meet
numerous Federal Motor Vehicle Safety Standards and then certify compliance.
Workers at Reading Group install a utility body on a Ford SuperDuty chassis. Upfitters must meetnumerous Federal Motor Vehicle Safety Standards and then certify compliance.

Stock or custom

The chassis (a truck without a body) is usually the most expensive part of a work truck, so customers often start by picking a make and model.

Large fleets will special-order chassis and have them drop-shipped to upfitters, where customized bodies will be installed. The smaller the fleet or customer, the more likely he’ll buy a chassis, and often a complete work truck, from stock, says Craig Bonham, vice president of sales at The Reading Group in Reading, Pa.

“Replacing a truck is typically done after cardiac arrest of an old truck,” he says. “It’s a procrastinating market. They won’t buy until they absolutely need it, and then it’s right now.”

Manufacturers such as Reading assemble standard bodies for quick fitting to stock chassis, which body distributors and truck dealers have on their lots for a customer to come by to grab a new vehicle – “a truck that’s ready to bump the curb, bust bugs and burn fuel to go down the road,” as Bonham puts it.

Reading also modifies standard bodies with special equipment and builds custom bodies for fleets whose managers plan ahead.

“If you’re buying a chassis from stock, coordinate with the upfitter to make sure that what you have in mind for a body will work,” says Corey Stanley, director of account management at Auto Truck Group, a major upfitter headquartered in Bartlett, Ill. Truck dealers keep some bare chassis in stock, and so do bailment pools supported by major chassis builders on lots around the country. Dealers and pools also stock completed work trucks with popular basic bodies.

“Right now we’re getting ready for spring, and are starting to build landscaper dump bodies for stock,” Stanley says. “Through history and market research, we try to make educated guesses and educated assumptions about what’s needed and will sell.”

Auto Truck Group produces utility-bodied work trucks for specific
customers, and will stock them when it knows that a customer will later take delivery.
Auto Truck Group produces utility-bodied work trucks for specificcustomers, and will stock them when it knows that a customer will later take delivery.

Frames & electricals ready

In recent years, truck makers have made great strides in laying out the frame, electrical system and engine equipment with work bodies in mind, says NTEA’s Strine. On many chassis, the CA, or Cab-to-rear-Axle area, is “clean,” meaning nothing is mounted above or outside the main rails, and if it is, it can be moved out of the way to accommodate bodies that straddle those rails. Frames in chassis destined for commercial service are usually straight, with few or no humps, and heavier models position rails at an industry-standard 34 inches apart.

Diesel exhaust aftertreatment equipment is hung below the chassis frame, and vertical stacks on heavier models are compact and intrude as little as possible into the CA area, Strine says. Tanks for diesel exhaust fluid are either placed under the cab or, if one is on a frame, it usually has long lines so it can be moved by the upfitter and still work.

Exhaust systems are regulated by the Environmental Protection Agency and laid out with bodies in mind. It’s best to spec the right system for a specialty body instead of trying to modify it later with expensive OEM-supplied and EPA-approved kits.

Never cut into a truck’s wiring harness. There are thousands of circuits on modern trucks, and cutting into wires can affect the operation of something seemingly unrelated to the wire’s main purpose. For instance, a breached tail light wire might interfere with the shifting of the automatic transmission.

Instead, OEMs provide “body builder” connectors at locations on the frame, and switches in the cab. Body wiring should be made with connectors that will mate to the ones that an OEM uses. If they’re not compatible, change the body builder’s connectors, not the OEM’s.

Few work trucks are as fancy as this Peterbilt with its J&J aluminum dump body. Its owner in New York enjoys taking it to shows.
Few work trucks are as fancy as this Peterbilt with its J&J aluminum dump body. Its owner in New York enjoys taking it to shows.

Today’s multiplexed chassis wiring offers considerable flexibility for hooking switches to specialized functions in the body, so nothing under the dashboard needs to be cut into, either.
Every OEM publishes a body builders Book for 3/4-ton and heavier chassis. These are available on manufacturer websites, on CDs and in printed form, notes Stanley at Auto Truck Group. NTEA also has a Body Builder’s Guide listing federal regs and how they affect body design.
Length, weight and corrosion

The most elementary starting point for any kind of body is its length. For instance, a utility or service body might be 8, 9 or 11 feet, and that will determine what the chassis’ CA dimension in inches should be. An 8-foot body might well go on a 3/4-ton pickup chassis. Conversely, a customer wanting a body for a pickup from which a 6- or 8-foot bed has been removed will need a 6- or 8-foot body, but nothing longer. A larger and heavier body needs a heavier cab-chassis model with a longer frame for proper support.

“Upfitters should always strive for the lowest mounting possible without interfering with vertical travel of the rear wheels, or with fuel tanks and other chassis equipment,” Bonham says. “Low mounting helps with stability. But we don’t have any control over how the customer loads the body. He may put heavy items in the superstructure and lighter items on the floor. If he puts a ladder rack on the top of the body and loads it with 1,500 pounds of ladders, that will affect stability, stopping and how the vehicle handles.” So both sides should communicate about how exactly a body will be used.

Assuming stability is handled, buying a stock body doesn’t preclude mounting heavy equipment, such as a welder or air compressor, because the body can be reinforced by installing supporting channels inside cabinets, says Stanley at Auto Truck Group. A better idea is to buy a stock body built with that equipment in mind, or with it already installed. His company assembles and stocks utility bodies with cranes and air compressors for mobile service work – a “mechanic’s truck” whose body might be worth $50,000 to $60,000, surpassing the value of the chassis.

A body’s desired service life also affects its construction. Road salts attack all metals and can shorten the body’s life, but metals can be chosen to fight it off. For about 60% of its bodies, Reading Group uses steel that’s galvanealed, where zinc is molecularly bonded instead of dipped in hot zinc, as is galvanized steel. The other 40% are made of aluminum, which is more corrosion-resistant and also lighter in weight. Multi-stage electrostatic coating and paint are applied to all units.

This railroad maintenance-of-way truck has a heavy utility body and knuckle boom with a claw to handle wood track ties. Outriggers keep it stable.
This railroad maintenance-of-way truck has a heavy utility body and knuckle boom with a claw to handle wood track ties. Outriggers keep it stable.

An even better material is fiberglass, according to Dave Williams, Verizon Fleet Operations’ regional manager for New York. Verizon gets its utility bodies from Fibre Body Industries in Keller, Texas.

“It’s lighter, holds up well and keeps its appearance better, which is important for image,” he says. “Fiberglass is more costly to repair after accidents, but you avoid rust from salt water. I haven’t seen a steel body yet than can withstand the corrosion, especially now that they’re using these aggressive salts on the roads.”

Many details in dump bodies

As with other types of work-truck bodies, body length is the place where Ed Monk, Northeast regional sales manager at J&J Truck Bodies in Somerset, Pa., starts in quizzing customers about their dump needs. These can get complicated and a little alarming for truckers, who probably are not aware that they might legally need high-mounted lights and rear bumpers.

For a heavy truck, “often it’s an 18-footer,” he says of the body length.

“That tells me about the chassis’ axles – 46,000-pound (capacity) rear and 18,000 or 20,000 front, plus maybe a lift axle.” If it’s a bridge state, Monk says, you can go to a seven-axle chassis. The frame – the dealer has to get it right, with tall rails or reinforcers, but Monk says he looks at the frame as well.

“What’s the load weight and what are you hauling, plus size of the material hauled? The type of material determines whether the body’s steel or aluminum. Aluminum is popular in all states because of its light weight; it averages 1,500 pounds lighter than a comparable steel body. If you haul by the ton, aluminum has a payoff.”

The capacity in cubic yards is the next concern, Monk says. This affects the height of the sides, which can be increased with wood risers.

Other details include:
• The type of tailgate (double-acting, barn-door or high-lift);
• The load-containing tarpaulin;
• The number and placement of lights. Some customers want more lights than the minimum required by Federal Motor Vehicle Safety Standard 108, but don’t realize that the standard requires them at the body’s upper-most corners, meaning on the cab shield and at rear of the box;
• The type and make of a hoist mechanism;
• Where hydraulic controls should be mounted;
• The possibile need for an air feathering valve to finely control body tilting? (Snow plow trucks often do.)
Then there’s rear overhang.

Overhang and bumpers

“Overhang at the rear becomes very critical when hauling asphalt to a paver,” Monk says. “Also with mounting salt spreaders. With a snow plow, you have to spec the correct front-axle capacity on the chassis. That depends on bumper-to-axle distance; if it’s a rear-set axle, that 4,000-pound plow through leverage can become 5,500 pounds. If you’re buying a used chassis, find out whether the OEM allows it to be used with a plow.”

Rear overhang is also important because of an obscure 1952 federal law requiring bumpers on any truck whose body extends more than 2 feet beyond the tires of the last axle, he says. [Details are in the Federal Motor Carrier Safety Administration’s regulations at 393.46(b).]

This law has long been ignored, or local judges have thrown out citations because bumpers interfere with a body’s operation. No more.

Local police officers are learning about that requirement and are writing tickets for drivers of dump trucks that don’t have bumpers. Monk calls them by their old name, “ICC bumpers,” because they needn’t be energy-absorbing rear impact guards later required on trailers by federal authorities.

“If the overhang of the tailgate or spreader apron (the sheet-metal lip that guides asphalt into a paver) exceeds 24 inches, as measured from the rear of the center of the tires, you need an ICC bumper,” he says. “Sometimes we have to install a removable bumper that the driver needs to remember to remove before dumping, then put back on. And it weighs 40 or 50 pounds. It’s become quite an issue.”  

Verizon’s work truck specs

Dave Williams, Verizon Fleet Operations’ regional manager for the state of New York, offers an example of some things to consider when spec’ing work trucks.

Verizon has Ram 2500s and 3500s, older GMC 4500s and now heavier Freightliner M2 chassis with utility bodies, and some with man buckets. The majority of Williams’ 9,300 trucks are cargo vans, mostly Chevrolet Express 2500s.

However, Verizon now uses lightweight fiber-optic cable instead of copper cable, so it doesn’t need the capacity of full-size vans as much anymore. So it’s going to Ram CVs, commercial vans based on the Dodge Grand Caravan minivan.

“Anybody can drive ‘em,” he says, “and everything [the installer or repairman] needs fits inside” on racks and shelves, except a 28-foot extension ladder, which rides on a roof rack clamped to drip rails. Exterior steel hardware is anodized against corrosion.

Though tall Euro-style vans with their small, fuel-efficient powertrains are catching on as work trucks as well as package carriers, Williams says Verizon doesn’t use them because their high roofs would collide with overhanging tree branches in residential neighborhoods. That’s another example of buying, or not buying, for the application.

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