Great ExSPECtations

Updated Nov 28, 2012
Caterpillar’s CT660 vocational truck can be configured for heavy haul. The CT660 chassis features a set-back axle, with both 116-inch and 122-inch bumper to back of cab lengths available.Caterpillar’s CT660 vocational truck can be configured for heavy haul. The CT660 chassis features a set-back axle, with both 116-inch and 122-inch bumper to back of cab lengths available.


Whether it’s hauling dirt, debris or equipment, heavy trucks on the jobsite play the simple, yet integral, role of moving things from point A to point B.

Unfortunately, because of the basic nature of a truck’s job, contractors may approach the purchase of a new Class 6-8 truck as a simple exercise. Some go for the cheapest build that will match the bare minimum of what they require, others opt for a truck that will handle whatever they throw at it regardless of the price and still others go with what they or their predecessors have always bought.

It’s easy to understand why so many choose a tried-and-true method. With so many vocational truck configurations available it can seem impossible to find just the right combination. But doing the right research can save you money – or at least the hassle and time of dealing with a truck that doesn’t cut it.

“We know that a lot of people didn’t buy trucks from 2007 on. So the average operating age for many of the trucks being used right now is in the 5- to 8-year range.”

Bob Nuss, owner of Rochester, Minnesota-based Nuss Truck and Equipment, says he sees customers of all experience levels come to his firm for assistance buying a vocational truck. But because of the economic downturn and the many changes emissions regulations have brought to the construction industry, Nuss says many contractors haven’t bought for some time and are not completely familiar with recent changes.

“We know that a lot of people didn’t buy trucks from 2007 on. So the average operating age for many of the trucks being used right now is in the 5- to 8-year range,” Nuss says. “In some areas it’s even older. Because of that, many customers don’t understand the SCR engines and diesel particulate filters (DPF). They’re looking for information.”

So, what should you be looking for when buying the right truck for your operation?

Doing the research

First, think through exactly what it is you’ll be using the truck for and where you’ll be putting it to work. Will you be moving dirt or other materials around a hot jobsite or hauling equipment in a colder climate? Curtis Dorwart, vocational truck marketing product manager for Mack Trucks, says upfront cost aside, “The truck has to make money for you. You don’t want something that isn’t going to get the job done with good efficiency and up time.”

Peterbilt’s Model 365 is available in both set-forward and set-back front axle configurations. It can be built as a day cab or with a Unibilt sleeper and is available with four engine configurations with up to 485 horsepower.Peterbilt’s Model 365 is available in both set-forward and set-back front axle configurations. It can be built as a day cab or with a Unibilt sleeper and is available with four engine configurations with up to 485 horsepower.

Be thorough in considering all the ways you’ll use a new truck, the environment it will run in, as well as terrain, weight restrictions, environmental laws and necessary power.

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For those new to the business, Dorwart recommends asking around and taking a look at what other contractors in your area are doing as an initial point of reference. “There are many local regulations regarding lift axles, the Bridge Formula, and so on, so there is no ‘one size fits all spec,’” he says. “But taking a look around is always a good first step. This will help to ground you.”

Randy Smith, marketing segment manager for Freightliner Trucks, says he sees many contractors under-size, or purchase a truck that is light on specs. But since most contractors purchase trucks with the intent to keep them for several years, “It might initially seem like the right business decision … but it can ultimately result in expensive operating costs,” Smith says.

Dorwart says the homework is critical. “Really ask yourself … how much weight do you need to or want to haul?” he says. “Do you want to sacrifice some payload for productivity with a larger and heavier engine? Do you really need to have 100 gallons of fuel on board, or will 80 be satisfactory? How long are your trips? And how fast do you want to run? Are you loaded both ways?”

“All of those factors will play into how best to spec the truck chassis – which in the end is a bit of a dance in trying to balance weight, productivity and durability to mention a few,” Dorwart says.


After nailing down exactly what it is you’ll be putting a truck through, you’ll want to contact your dealer and begin discussing several important specs, beginning with the base configuration. This includes grades, weight, terrain, application and speed, Nuss says. “And if we know how far he’s going to travel, we can figure out fuel.”

If you haven’t spec’ed a dump or equipment-hauling truck before, make sure you find a dealer nearby, Nuss adds. “If you don’t run more than 100 miles away from home, stick to somebody you can get service from that knows your area.”

“…the bridge laws vary so much in each state. Some states will recognize a pusher or a quad axle. Then there’s California or Illinois where they don’t recognize a pusher.”

With the job, terrain, environment, expected grades, surface conditions and, most importantly, the Bridge Formula, in mind, choose a set-forward or set-back front axle. The Bridge Formula is another good reason to work with a dealer that knows your area, Nuss says. On the Interstate, the Bridge Formula limits the maximum weight axles are allowed to bear. “We’ve had so many guys come in with a long wheel base truck that were unable to make their bridge limits, and then they have to stretch the truck at a lot of expense,” Nuss says. “And some guys will go to North Carolina, for example, and buy a 210-inch wheelbase when the area they’ll mostly be running in needs a 230-inch wheelbase.”

Apart from the Bridge Formula, federal law restricts a single axle to bearing 20,000 pounds while axles less than 96 inches away from one another may only bear 34,000 pounds. “The bridge laws vary so much in each state,” Nuss adds. “Some states will recognize a pusher or a quad axle. Then there’s California or Illinois where they don’t recognize a pusher. So it’s important to understand local and state laws.”

For those who will need to haul heavy loads on the Interstate, a set-forward front axle is likely the best choice since it provides a longer wheelbase and thus can be loaded to a higher weight than a set-back axle, according to the Bridge Formula. However, if weight isn’t a concern and you’d like more maneuverability, the set-back axle has a lower turn radius.

Dorwart adds that suspensions are another important spec to think through. Considering whether you’ll be operating off-road, the big question is spring suspension versus air suspension. “Air can save weight, but it may not be as durable as a spring suspension,” he says. “How long do you plan to keep your truck? Don’t forget about resale value. The residual value of the truck can really make the difference on the return of investment.”

Each manufacturer that spoke to Equipment World recommended including the body builder in the discussion early. “Understand what they can offer and what specific needs they may have to mount a body,” Dorwart says. “There is little worse than spec’ing and building the truck and then you find out from the body company that the fuel tank is too large and interferes with a hydraulic tank. Or the wheelbase is wrong and then you end up with a frame that looks like Swiss cheese after having to re-drill everything.”

Insist that your dealer provide a chassis layout to your body builder prior to building, says Jim Zito, vocational sales manager for Peterbilt. “As chassis-mounted components and emissions aftertreatment systems change, a little bit of time invested up front can avoid significant delay and expense putting the truck into service,” Zito says.

You’ll also need to decide whether a steel, aluminum or hybrid body is best for your application. “One will net you great weight savings but may limit the type of payloads you can safely carry or carry without breaking something else,” Dorwart says.

Along with axles and suspension, Smith recommends keeping brakes in mind. “This decision will play a big role in your total cost of ownership,” he says. “Make sure you request a weight distribution calculation (from your dealer) once you have a completed spec. This will give you confidence that you have the correct wheelbase, frame size, axle and suspension ratings.”

When it comes to the engine and transmission, Smith says selecting an underrated powertrain to reduce the upfront cost can lead to an expensive total cost of ownership. “Performance and fuel economy are important in a vocational vehicle. When spec’ing engines and transmissions, consider all of the available options,” he says.

Finally, in addition to a comfortable cab and telematics, Smith recommends working with your dealer on chassis/mid-chassis packaging to ensure that air tanks, fuel tanks, diesel exhaust fluid (DEF) tank, batteries, cross members, exhaust and other components are in the correct location. “The goal is to package everything so that the manufacturer does not have to move any components when installing the body/equipment,” Smith says.

“If the truck’s set up right to do the job, it will perform properly and you’ll max your performance each day,” Nuss says. “It’s all about making as few trips as possible.”



Western Star


Western Star’s Class 7 4700 Crane, Roll-Off truck is available in set-forward and set-back day cab configurations and with a wide variety of fifth-wheel options that provide a solution for bulk haul, local delivery and construction applications. The 4700 incorporates a high-visibility hood and a variety of lift axles for vocational applications. The company’s Class 8 4800 and 4900 series trucks are designed for dump and mixer applications. The 4800 series has a 109-inch distance from the bumper to the back of the cab (BBC) and is designed for demanding construction, government, refuse and utility use. The versatile 4900 product line is suited for long-haul and severe duty vocational applications. The 4900SF, 4900SB and 4900XD feature a 123-inch BBC. The 4900 EX has a 132-inch BBC extended hood version. All Western Star models can be equipped with the Detroit family of engines with power ratings from 350 to 600 horsepower.

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The Peterbilt Model 367 is designed for a variety of dump, mixer and construction applications. The Model 367 features a 123-inch distance from the bumper to the back of the cab, and is available in both set-forward or set-back axle configurations, as a day cab or with a Unibilt sleeper. The lightweight, huck-bolted, all-aluminum cab with lap seam construction and bulkhead style doors resists corrosion and is designed to provide years of watertight performance. The Model 367 is also available with the lightweight PACCAR MX engine to optimize payloads. The gently sloped, long-length hood on the truck enhances visibility and allows for a 1,438 square-inch radiator to accommodate engines of up to 600 horsepower. The Model 367 can be spec’ed with a variety of heavy duty components including full and partial frame liners, as well as a selection of axles including tandem, tridem and lift-axle options.

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The Kenworth T800 dump truck features a set-back front axle to optimize payload potential and maneuverability, front and rear PTO options to meet unique application requirements and is engineered specifically to the application for added longevity and life cycle value. The T800 can be spec’ed with engines rated with a wide horsepower range, offers several radiator sizes up to 1,780 square inches for added cooling, and has a variety of rear axle ratings to meet specific customer applications requirements.

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International’s WorkStar trucks are designed to stand up to the rigors of the jobsite and can be spec’ed with the powertrain combinations, axle types and enough engine power to quickly maneuver through a workload. The all-steel cab design has no rivets to reduce leak paths, features a one-piece door frame, five-point corrosion protection and an optional sloped hood. WorkStar trucks can be configured with either the MaxxForce 11 or 13 engines, which offer up to 390 and 475 horsepower respectively. These trucks can come with either manual, automated manual or automatic transmissions, two front axle types and three rear axle types.

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The Freightliner 108SD/114SD and Coronado 122SD were developed specifically for vocational applications and are available with an array of options, including body-specific chassis layouts. Available in both set-forward and set-back axle configurations, engine offerings range from 6.7 to 16 liter and horsepower/torque ratings are available to meet truck spec requirements between 200 to 600 horsepower. Compressed natural gas and liquefied natural gas configurations come in several truck models and hybrid powertrain is available in some truck models. These trucks feature frame rails and reinforcements to optimize strength and increase load weight capacity. Front and rear engine PTO offerings are available on some models.

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Caterpillar’s CT660 vocational truck supports a wide range of body types for aggregate, asphalt, civil construction, concrete, heavy haul, paving, road construction, site construction and more. The chassis features a set-back axle, with both 116-inch and 122-inch bumper to back of cab lengths available. Eaton automated manual and fully-manual transmissions are available in 10 to 18 speed options. Front axles and suspensions on the CT660 range from 12,000- to 23,000-pound capacities while rear axles and suspensions range from 40,000- to 58,000-pound capacities. For a lighter body, the CT660’s cab is 100 percent aluminum and features a hood made of Metton, a lightweight material Cat says is much smoother and stronger than fiberglass. The CT660’s interior features reduced noise from previous models and Cat designed all interior switches to be large enough to be operated with gloves on. All controls are close enough to allow the driver to safely operate the vehicle without having to reach too far, creating a potentially dangerous driving situation.

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Mack Trucks

Granite SeriesGranite Series

Mack’s Granite Series and Titan by Mack models are available in configurations that cover most jobsite applications. The Granite Series comes in both set-forward and set-back axle configurations and can be equipped with Mack’s fuel-efficient MP7 or MP8 engines. The MP7 has a horsepower range of 325 to 405, while the MP8 provides between 415 to 505 horsepower. Granite series trucks are available in dump, mixer, roll off, tractor, and more models. A heavy equipment model of Mack’s Titan series for long-haul applications is available. Titan trucks are powered by Mack’s MP10 engines. The standard configuration provides up to 605 horsepower with a torque rating of 2,060 foot-pounds at 1,200 rotations per minute.

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Volvo says its VHD models are engineered so truck body builders can deliver trucks as quickly as possible to the customer. The Volvo VHD features a spacious cab with extra room between the seats and plenty of storage for personal gear. The VHD also offers insulation and soundproofing that Volvo says keeps the cab as quiet as most passenger cars. Doors are double sealed to keep out water, wind and noise. Keeping in mind that not all vocational assignments are day jobs, Volvo designed the VHD 430 with a sleeper berth. The VHD features a high-strength steel cab, three-point seat belts and driver-side air bag.

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