5 Tips for Dump Truck Shoppers

The right choices of engine, transmission, axle configuration and other features ensure that your truck fits your needs cost-effectively
5 Tips for Dump Truck Shoppers
A Volvo dump truck heads down the road. Truck and dump body dealers should be involved early in the buying the process to determine the best fit and features for the job. (Photo courtesy of Volvo Trucks North America)

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If you’re like most onsite system contractors, you buy a dump truck for one reason — to make money. The best way to do that is to resist the temptation to buy more performance than you need, yet also avoid skimping on the features that enable your truck to work most productively in your applications.

Whether you plan to buy a new truck or search for the best-fit used model, here are some ideas to help you buy no more and no less truck than you need.

Work with your team

You’ll be money ahead to include your truck and dump body dealers early in the process of specifying the features you want, notes Steve Ginter, vocational product manager for Mack Trucks Inc. “Make them partners in your buying decision,” he suggests.

“Your truck dealer’s knowledge about truck performance and needs in your local area is priceless — from helping determine the appropriate gross vehicle weight rating and suspension, to the best gearing and the most appropriate tires,” Ginter says. “This kind of information can help you strike a good balance between the size of your truck and how well or how quickly it will pay off.”

Meanwhile, he notes, your dump body dealer can help you select the type and capacity of the dump box and the best location of such components as battery boxes, air tanks and hydraulic fluid tanks. One critical decision concerns the clear CA (cab-to-axle) dimension — the distance from the back of the cab to the center of the bogie — needed to match the length of your dump box. Clear CA allows for any back-of-cab obstructions, like an exhaust pipe or stanchion.

Another choice is the material used to build the dump body. An aluminum body, which can increase payload while saving fuel, may be adequate for handling sand for drainage or small stone, Ginter notes. “However, if you frequently encounter large rocks on your excavation project or switch between hauling sand one day and riprap the next, a steel dump body will be more durable.”

And don’t forget to discuss tires and wheels with your truck dealer. Weight-saving aluminum wheels clean easily. Also, compared to conventional steel wheels, they can increase payloads while dressing up your company image.

When it comes to choosing tires, tread design isn’t the only factor to consider. “For some reason, tire preferences can vary from one region to the next,” says Wade Long, marketing product manager for Volvo Trucks North America. “Equipping your truck with a type and size of tires popular in your area means replacement tires will probably be more readily available.”

Consider maneuverability

Truck manufacturers generally offer a choice of two locations of the front axle — axle forward, where the axle is mounted about 28 or 29 inches behind the bumper, or axle back, where the axle is placed farther toward the rear of the truck.

In addition to affecting allowable axle weight limits and payload axle weight transfer, the location of the front axle affects turning radius. As Long notes, an axle-forward design provides about 40 to 45 degrees of wheel cut. However, an axle-back design, in which the axle is positioned 52 inches behind the bumper, shortens the wheelbase, providing about 50 degrees of wheel cut for a tighter turning radius and easier maneuvering in cramped quarters.

Weigh hauling needs

Another basic decision involves gross vehicle weight rating (GVWR). It determines the size of your payloads. It also has a direct bearing on choice of number and load capacities of the axles to stay within legal weight limits.

To reduce damage to federal highway roads and bridges, federal law limits the gross weight of trucks based on the number and spacing of axles. The shorter the distance between front and rear axles and the fewer the axles, the lower the weight permitted per axle. The maximum allowable weight is 34,000 pounds for a tandem axle and 20,000 pounds for a single axle. As a result, under the Federal Bridge Gross Weight Formula, a 25-foot, three-axle dump truck would have a gross weight limit of 54,000 pounds.

Frequently, Ginter notes, a dump truck with a 38,000-pound rear axle and an axle-forward design is equipped with an 18,000-pound front axle. In this case, a heavier-rated front axle usually isn’t necessary, because the axle-forward configuration makes it difficult to transfer much more of the truck’s weight to the front axle. However, for the same dump truck equipped with an axle-back design, a 20,000-pound front axle would be appropriate to handle the additional weight transferred from front to back with this axle position.

Choose the proper engine

Buying more horsepower than you really need can waste money. If you’re not usually pushing GVWR limits, a smaller engine may be a good choice. At the same time, though, a lower-horsepower, lighter- weight engine can give you more payload capacity, if needed.

You may not need extra horsepower if you’re operating on mostly flat jobsites and roads. Also, a more powerful engine generates more torque, which requires stronger and more expensive engine and drive-train components.

“In general, if you don’t usually operate at full GVWR, a smaller-displacement engine may be a better choice,” Long says. “But if you operate in hilly or mountainous terrain and you want to maintain good startability and keep up your road speed on grades, then you’ll probably be more satisfied with a larger-displacement engine.”

Evaluate transmissions

Manual transmissions, with a wide range of gear options, remain the most popular choice. More gear choices, of course, also improve your ability to match engine speed to your job. A low gear with a low range can prove helpful in keeping your truck moving in mud or sand. A multi-speed reverse may save you time, if your work involves backing long distances.

Although more expensive, an automatic transmission with a flexible torque converter makes up for its fewer gears and offers its own advantages. It doesn’t require the shifting, which may be important in the case of a new driver or where multiple drivers with different skill levels operate the same truck. An automatic transmission also eliminates the expense of maintaining and replacing clutches. And with no clutch pedal, the driver is less fatigued at the end of the day. That can be an attractive feature for older, experienced drivers as well as new drivers, Ginter says.

In addition to driver skills and preferences, terrain is another factor to consider in deciding between manual or automatic. “If you drive in relatively flat country, a 10-speed manual or a six-speed automatic transmission may be appropriate, depending on engine size,” Ginter says. “However, if you’re working in steep hills or mountains at high GVW, a 13-speed or even 18-speed manual transmission may be a much better choice.”

Another option combines the best of a manual and automatic transmission. Priced between these two transmissions, the automated manual transmission is gaining popularity. It eliminates the clutch and the hand shifting of a manual transmission. Instead, electronic sensors, processors and actuators do the shifting to match travel speed with the load and job application.

An automated manual transmission can also help cut fuel bills. It’s lighter and uses energy more efficiently than a conventional automatic transmission “Also, it takes the driver out of the fuel economy picture and prevents the engine from running at high rpm,” Long says. “With manual transmissions, many drivers shift at around 2,100 rpm and then reduce engine speed. Automated manual transmissions keep the engine in the range of 1,300 to 1,500 rpm.”

That reflects the electronic control technology of today’s engines. Conventional, mechanically controlled engines produce maximum torque at about 1,800 rpm, Long notes. The torque of engines controlled electronically peaks at 1,200 rpm.

Your truck dealer can explain these and other considerations in much more detail. However, these basic tips should get you off to a good start in making a smart dump truck buying decision.

Greg Northcutt is a freelance writer based in Port Orchard, Wash. He can be reached by email at editor@onsiteinstaller.com.



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