Dump Spec'ing Tips

If you're in the market for a dump truck, it's important to do your homework. Unlike some other vocations, dump truck specifications are very regionalized, so what works in one area of the country will not work in another. Brian Lindgren, vocational market sales director for Kenworth Truck Co., relates tips dump truck fleets should consider when they are looking to purchase new equipment. Before you

If you're in the market for a dump truck, it's important to do your homework. Unlike some other vocations, dump truck specifications are very regionalized, so what works in one area of the country will not work in another. Brian Lindgren, vocational market sales director for Kenworth Truck Co., relates tips dump truck fleets should consider when they are looking to purchase new equipment.

“Before you start looking at sticker prices, you've got to do something else first: Find out what the length and weight regulations are in your state,” says Lindgren. “The goal here is to try to take maximum advantage of the weight laws to maximize payload. Some states [mostly in the West] require compliance with the Federal Bridge Formula, yet others don't. This will have a big influence on how the axles are set up and spaced.

“A ‘Bridge Formula’ truck will tend to be longer to spread the weight, so you may need to have lift axles, but there are different rules on how much load you can add with lift axles. And some states don't allow pusher axles. Your dealer should know the rules and regulations. In states where you don't need to comply with the Bridge Formula, you can spec trucks shorter and heavier, making them more maneuverable on job sites.”

LOAD & HAULING QUESTIONS

Lindgren says some key questions that need to be answered concern the loads to be hauled. “For example, you will need a different chassis spec when hauling bulk loads such as asphalt, sand or gravel than you would if you hauled mostly demolition debris.

“Are you going to spend a lot of time on very rough job sites? Or will most of the hauling be long distances on smooth gravel and sealed roads?

“If you will be going off-road a lot into rough terrain, you'll need a suspension that is heavier duty and has more articulation. But if you'll be hauling longer distances, you'll need to consider the trade-off between the ease of dumping and the ability to haul more loads per trip. For example, a transfer dump will allow you to haul more with one driver, but it will take longer to unload. Double bottom-trailers carry a lot of payload, too, but with those you're limited on where you can drop the load; it's a lot harder to dump gravel into a hole for a swimming pool, for instance, with bottom dumps.”

CONSIDER POWER

He says one of the big mistakes fleets make with dump truck engines is to spec too much power. “You should get just enough horsepower to do the job and, generally, 350 to 400 hp. is plenty for most applications. Extra horsepower just uses more fuel, puts more strain on the rest of the drivetrain, and adds cost up front.”

Weight savings are important to consider as well. “If you go with a smaller 12-liter block, you save around 700 lbs. over a 14- or 15-liter block. The transmission put behind the engine needs a lot of ratio range. You need a low enough gear to get out of a hilly job site and high enough top gear to attain decent highway speeds.”

If you are hauling over 90,000 lbs., consider an 18-speed, he suggests, because you get closer splits from bottom to top.

“Rear axle ratios should be matched with the transmission so that engine speed is around 1,600 rpm at highway speed and side-to-side differential locks for traction are recommended.

“A little money spent up front on a better air cleaner is cheap compared to a dusted engine,” he adds. “And better filtration will usually mean longer life for the filter elements. For example, dual 15-in. air cleaners will last over seven times as long as a single 11-in. underhood air cleaner before needing replacement.”

WATCHING YOUR WEIGHT

If you are hauling a lot of loads per day, cutting vehicle weight can be profitable, Lindgren points out. “You can slim down by spec'ing components, such as wheels, air tanks and clutch housings, in aluminum rather than steel. Use the smallest fuel tank you can get away with, as that saves weight as well. Some operators can get away with a 56-gal. tank, but most will need at least 75 to 90 gal. to get through a day. You can also save valuable pounds by choosing the right suspension, as the difference can be as high as 400 lbs.

“To avoid hauling around extra steel in the vehicle frame, have the dealer work with an OEM application engineer so that you only get enough frame where you need it. You will typically need an extra strong crossmember at the back of the cab to strengthen the hoist mounting area. If you are planning to add lift axles later, make sure the dealer includes that information to the order so that the frame can be prepared for them.”

Lindgren advises that many of these weight-saving options can cost more up front, so you may need to balance that against the gains in revenue you expect to make hauling more payload.

“To get the best turn performance and road feel from steering, spec dual small gears rather than a large, single steering gear,” he adds. “The dual system will also last longer than a single system.

“Think about selecting low-replacement cost windshields when they are available. Most vocational fleets replace at least one windshield side per truck per year and two-piece, flat-glass windshields with roped-in seals can be replaced in half an hour for a total cost of under a hundred dollars. This can save thousands of dollars over the life of the truck.”

With lift axles, he says it's smart to get a six-channel ABS. “Lift axles, especially steerable ones, are normally over-braked for the load so by including them in the ABS system, they're less likely to lock up and you reduce tire flat spotting.”

Finally, for a small price in cost and weight, Lindgren suggests treating drivers to more room and quieter cans. “For example, Kenworth's Extended Day Cab gives the driver 6 extra in. of room fore and aft, and 5 in. more headroom. Kenworth's QuietCab option reduces in-cab noise by two decibels, meaning it cuts perceived noise by almost 50%. Options like these can dramatically reduce driver fatigue, and that helps keep them more productive.”

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