Charles “Chuck” Carew will tell you that in the concrete industry, weight, vehicle productivity and driver comfort are critical factors in mixer truck design, for they all affect the fleet's bottom line.
As the north region maintenance coordinator for the Florida materials division of Cemex Inc., Carew is in charge of maintaining roughly 1,100 mixers and 300 pieces of other equipment — from tractors to block and straight trucks — operating throughout the middle portion of Florida.
Starting with weight, Carew points out that a lower tare weight translates into more payload carrying capacity and thus more revenue. That means no change is too small to contemplate when it comes to weight savings. For example, the company now specs 42 gal. fuel tanks versus its previous 52 gal. option to wring a few more pounds out of the chassis.
Vehicle productivity is a broader metric that includes everything from fuel economy to reliability, durability and cost of maintenance. For example, sipping fuel while maximizing uptime means a truck is on the road more, making more money while spending less of it at the pump, says Carew.
Finally, there's driver comfort: soft, supple seats, AM/FM radios, and air conditioning being the most prominent factors. “That relates to productivity as well, for trucks that are comfortable to drive attract and keep good drivers — and trucks don't operate without drivers,” says Carew, noting that Cemex operates a variety of truck brands, from Peterbilt to Volvo, Navistar and Oshkosh.
“Right now, the trucking business is about keeping drivers happy,” adds Alan Otto, president of sand and gravel hauler Otto Trucking in Mesa, AZ. “When you have the best trucks on the block, drivers are less likely to jump across the fence to drive someone else's trucks.”
Still, putting a productive truck in the hands of drivers — light enough to maximize payload yet durable enough to survive the rough and tumble vocational operating environment — is the key to maximizing revenues and profits, says Mark Otto, the head of maintenance for Otto's fleet.
“We're restricted to 80,000 lbs. in Phoenix,” he says, noting that Otto runs T800 Kenworth tractors and trucks. “To lighten the load, we spec aluminum wheels and smaller engine blocks like the Cat C13 and Cummins ISX. But this is a tough industry and, while I try to make the trucks as light as possible, we need tough, durable trucks.”
“Vocational customers, especially in mixer and dump applications, benefit from lower operating costs and higher productivity available by selecting a lower cost engine with reduced weight and greater payload capacity,” says Gary Moore, assistant general manager for marketing and sales for Kenworth Truck Co., Seattle, WA. Moore also notes that vocational fleets can save over 500 lbs. by selecting the 11-liter Cummins ISM 425-hp. engine compared to a 13-liter model, while still getting the power needed for their specific application.
“It's a great choice for vocational customers who need a lot of power and weight savings for a bridge formula mixer or a super dump, for example,” he explains. “This engine option is especially useful for weight and cost-conscious operators and will help lower operating costs and enhance productivity, for every pound saved on the truck means one more pound of payload.”
Productivity calculations for construction trucks got a new wrinkle in 2007, when mandates to reduce exhaust pollution through the use of emission control devices added weight back into the chassis.
“Meeting the EPA [Environmental Protection Agency] '07 emissions standards added about 250 lbs. to our chassis, so we offered various options in aluminum to help customers reduce vehicle weight,” says Richard Shearing, manager of product strategy for Sterling Truck Corp., a division of Daimler Trucks North America, based in Reading, MI. Those aluminum options include cabs, air tanks, fly wheel housings, rear axle carriers, wheel hubs, wheels, battery boxes, bumpers, radiators and crossmembers, he notes.
“We also worked closely with each of our engine suppliers to ensure that we had the best possible fuel economy considering the emissions changes,” Shearing explains. Depending on the application, the fuel economy difference between '07 and pre-'07 in Sterling's construction trucks is 2% to 5%, he says.
Bob Bees, marketing product manager for Volvo Trucks North America, Greensboro, NC, adds that the fuel economy is the same or better than pre-'07 engines in Volvo's construction trucks, but notes that there is not much opportunity to recover the added weight of emission control technology, especially from the diesel particulate filter (DPF).
“We're constantly working to reduce vehicle weight,” he says. “The changes related to EPA '07 engines affected some body builders more than others, so we've gotten more clever about moving components around to meet these needs.”
Bees notes the DPF takes up space that was previously used by the battery box and/or fuel tank. This means either the fuel tank or battery box has to move into CA (cab to axle) space previously used for mounting the body or equipment. “For the most part, though, dump truck and mixers were not a problem,” he emphasizes.
Shearing says Sterling became proactive in visiting the body builders at the beginning of its EPA '07 development program so if issues arose, they would be early enough in the program that changes could be made to reduce the impact on the end user. “We were successful in providing clean back of cab solutions so that body builder installs remained efficient,” he notes.
“The objective was to design systems that didn't require exhaust modification or relocation by the customer wherever possible,” Shearing adds. “I think everyone in the industry is pleased with the operation of the EPA '07 compliant product. I think this can be attested to all the product validation that went into the trucks and components prior to the production release dates, meaning horsepower and torque levels have been maintained.”
Some construction truck fleets can't downsize their engine options simply because the nature of their work requires a lot of low-end torque a smaller-block model can't provide. While fleets can't make productivity gains on the weight side of the equation, OEMs are trying to give them productivity advantages through lower fuel consumption and better low-end performance.
Take, for instance, Mack Truck's 16-liter MP10 engine, a big-block diesel with up to 605 hp. and 2,060 lbs.-ft of torque. The MP10 adds the intelligent power management field proven by its siblings, the 11-liter MP7 and 13-liter MP8 engine, and all three are certified to meet the EPA '07 emissions standards, using ultralow sulfur diesel fuel and a diesel particulate filter.
“The MP10 offers a perfect balance between low-end power and high-speed horsepower for severe service applications like logging and mining, where drivers are carrying extreme gross combination weights,” says David McKenna, powertrain sales and marketing manager for Allentown, PA-based Mack. “It has a ‘hump’ horsepower curve, which means it has more power at 1,500 rpm than it does at 1,850 rpm. This encourages drivers to operate at lower rpm with greater power for greater fuel efficiency.”
McKenna notes that with about 38 hp. per liter, the engine hits the sweet spot of being sized correctly for brute power while still being optimized for fuel efficiency. For all its power, the MP10 is also a very quiet engine, with a harmonically balanced camshaft and insulated engine mounts to reduce noise, vibration and harshness.
“This is the art of modern diesel engines,” he says. “You get all of the components and subsystems to work in concert with each other. You manage the ways the fuel and air management systems interact with each other to optimize power at every engine rpm step.”
“Our research shows customers in the vocational segments expect their truck to have several key characteristics,” adds Steve Ginter, Mack vocational products marketing manager. “The truck has to haul heavy loads in brutal conditions. It has to be reliable, durable and efficient. And it needs the horsepower to pull extremely high GVW and GCW loads.”
Engine makers are also tweaking current designs to help fleets improve fuel economy, thereby boosting the productivity profile of their trucks.
Detroit Diesel Corp.'s EPA '07 compliant Series 60 engine, for example, is gradually being phased out and replaced by the new DD15. The company says a new software package is now available, free of charge, to help fleets recalibrate those engines to get better fuel efficiency from them.
“Extensive testing of the Series 60 has shown our particulate filter regeneration process is more effective than originally anticipated,” says David Siler, director of marketing for Detroit Diesel. “The fact that the filters are staying clean, combined with some advancements in the regeneration software, allow us to enhance the regeneration process to improve the fuel efficiency for the engines.”
These improvements, according to Detroit Diesel engineers, will increase fuel economy by up to 2.5%. Siler says fleets can take advantage of the modifications and associated fuel economy benefits by scheduling a visit to any Detroit Diesel dealer or distributor to have their EPA '07 Series 60 engine “re-flashed” at no cost beginning July 1 this year. He stresses that any EPA '07 Series 60 produced after July 1, 2008, will automatically be programmed for the modified regeneration cycle.
Making the entire construction truck package — cab, chassis, engine and body — fit together into a single, smoothly operating piece of machinery is the goal OEMs and their fleets keep aiming for.
Three years ago, for instance, Denton, TX-based Peterbilt Motors Co. introduced a new integrated chassis-body program for aluminum dump bodies and trailers with J & J Truck Bodies & Trailers. They will provide customers not only with one-stop shopping of a ready-to-work truck, but a lighter one that could haul more payload.
The dump bodies and trailers available through the program are the company's all-aluminum DynaHauler series that includes a wide selection of styles to accommodate numerous types of hauling applications, including sand, salt, asphalt, gravel, rock, wood chips, waste and recyclables, and scrap. For added convenience, Peterbilt says customers ordering through the new program receive a single invoice that includes both chassis and body or trailer.
“We're always looking at ways to reduce weight and improve fuel economy. Those are the two biggest topics of discussion in this industry right now,” says Ray Paradis, Peterbilt's vocational marketing manager. “This business is just so tough right now; fuel prices are a noose around the neck of many of our customers.”
Even minor changes to construction trucks can help fleets keep weight down, adds Paradis. He notes that Peterbilt offset the 250-lb. addition of EPA '07 mandated DPFs through a variety of small changes, such as a new power-assist steering system, that ended up saving 125 lbs. “We were redesigning our trucks anyway ahead of EPA '07, so we took that opportunity to look for weight savings anywhere we could,” he says.
Offering smaller engine blocks continues to be another big trend, Paradis notes. Peterbilt began offering Caterpillar's C9 engine in its mixer trucks three years ago as it helped take about 780 lbs. out of the chassis, versus a C11, and can be rated with comparable power. “Small engines are still going to be a trend in the construction market; very much so,” he says.
Better axle load distribution is another tactic OEMs are using to make their construction trucks more productive. For example, Navistar's new PayStar 5900i Set-Back Axle (SBA) model, introduced earlier this year, is built with wide-track, set-back axle design to address customer needs for front axle load distribution and improved maneuverability, says Phil Christman, vp and general manager of Navistar Truck Group's severe service division.
“The PayStar 5900i SBA introduction signals our commitment to building heavy-duty diesel trucks that perform in the most severe conditions,” he says.
The Paystar's aluminum cab, which reduces weight, also comes with a standard Whisper Cab sound insulation package for a comfortable environment for the driver, along with a more sloped hood for increased visibility on the job site.
These are the kinds of changes construction truck fleets are looking for today. “We need to be able to haul more without having to buy more trucks, while giving our drivers more comfortable and safer equipment to operate,” says Cemex's Chuck Carew. “That's what we're focused on for the future.”