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Photo: Hendrickson USA

It’s no secret that the world of solid waste collection vehicles is a rough, dirty, rugged one. Operating in all kinds of weather, working routes ranging from tight urban streets to bumpy landfill paths, alternating from empty to a full payload, these refuse workhorses endure some of the toughest conditions on the road. But thanks to the high cost of new trucks, tightening budgets, and rising populations, downtime is prohibitively expensive. Therefore, maintaining these robust rubbish trucks is critical.

Operators are required to do daily pretrip walk-around inspections. That includes checking brake adjustment, says Drew Larsen, general manager for Express Brake International in Ocala, FL. However, he continues, while drivers can easily check a lot of things, brake adjustment isn’t one of them. “It’s unrealistic for drivers to check brake adjustment, because they have to crawl under the vehicle to measure the pushrod travel. That’s not practical for most drivers. Most drivers aren’t familiar enough to know what to do.”

That means it usually doesn’t get done. Larsen says it’s “mainly reported when a driver notices it in the brake pedal. By then, it’s too late; there’s already reduced performance.”

The industry has known about the issue a long time, he claims, adding that some devices help “somewhat, but none are simple or user-friendly enough. There’s no easy means to for drivers to check brakes, so many aren’t doing it. Many fleets only measure when the truck comes in for service.” Quoting statistics that show a significant number of traffic fatalities—as high as 30%—involve trucks where brakes are a factor, he believes the market is ripe for Express Brake’s new product: Brake Alert.

At a cost of about $20 per wheel, the patented Brake Alert system does the looking for the driver by providing a simple inspection tool to check brake adjustment and brake life. Brake life is especially difficult to accurately detect because the dust cover or lip in the drum obscures the brake pads. With Brake Alert, instead of crawling under a vehicle to view the wheels under the truck, the driver looks at a small device mounted on the end of the S-cam.

If the system shows green, the brakes are good. If yellow appears, brake life is marginal. Red indicates brakes are worn nearly to or at the metal. For brake adjustment, the driver looks at the adjustment zone of the meter. Red indicates the chamber is over-stroking, caused by brakes being out of adjustment or from a bad slack adjuster.

“We wanted to give the driver something obvious, easy to read, and intuitive,” Larsen explains, “so we designed a three-color indicator.” The indicator is reflective, so it can even be seen at night with a flashlight.

Larsen explains how Brake Alert operates. It installs on the end of the S-cam next to the slack adjuster. A lining meter clocks with the S-cam; as the brake wears, it advances. A mechanic calibrates the brake adjustment meter during installation. The brakes are adjusted to the point of maximum allowable travel range, then a pin is set; if the pushrod ever goes beyond that point, it flags red.

Invented by a school bus mechanic and in development for more than a year, Brake Alert has received good feedback at trade shows and from trial fleets, Larsen reports. “It addresses a need in the industry with a simple, low-cost solution that helps fleets assure proper brake function. This kind of preventative maintenance will catch problems early.”

Express Brake International also manufactures brake shoes for heavy-duty trucks. Although traditionally, linings are secured to the brake shoe cores with rivets or bonding agents, Express Brake’s are neither riveted nor laminated, because, Larsen says, those processes didn’t work well. “They delaminated or ruined the shoes.” Express Brake utilizes a stainless-steel table and retaining system that provide higher sheer strength than rivets. “We put 26 square inches more lining surface area on the brake shoe to maximize the amount of lining in contact with the drum, providing significantly longer lining and drum life as well as 9% better stopping power.”

Whichever brakes are on a collection vehicle, Larsen believes that Brake Alert will help assure proper brake performance and that the Express Brake system can reduce the overall cost of braking for most fleets. “It’s an advantage for severe duty trucks that particularly applies to the refuse industry with all the stop-and-go.”

“Moni-tired”
Stop-and-go conditions affect more than just the brakes. “Heat is the issue,” contends Peggy Fisher, president of TireStamp in Troy, MI. “Stop-and-go braking can burn the base of the tires. The tires then catch fire.”

To prevent that situation, TireStamp offers sensors for the tire-wheel assembly to monitor the temperature. “We monitor heat and compare the heat on each axle,” Fisher details. “If one gets hotter, it could be due to dragging the brake or a frozen wheel bearing. It goes beyond the tires.”

There are other tire-pressure monitoring systems that light up in the dash, Fisher notes, but for about $10 per month, TireStamp’s proprietary system sends data to servers, where it is analyzed for accurate cold inflation. Proper cold inflation is needed for an accurate reading, but monitors also compensate for falling temperatures to preclude false alarms. After analysis, TireStamp delivers the information to “people who care, such as the fleet and maintenance managers and technicians,” who set the customizable threshold. If the pressure drops below the established threshold, alerts are sent via e-mail, cell phone, or other means to the delegated person. In addition, management can go to the portal for detailed reports.

“You never have to take inflation pressures again,” Fisher promises. That’s not the only time-saving measure offered by the monitoring system. One of the reports particularly popular with fleet managers indicates wheel position of vehicles in the yard in need of attention. “It allows them to go right to the specific vehicles.”

Fisher considers the system and the service a good return on investment that typically recoups its purchase price within a year. Marketed to the solid waste industry and commercial truck fleets, other benefits of this leading-edge technology include fuel savings, increased tread life, and increased tire life. “You have more retreads. It’s labor saving. It reduces downtime and improves productivity by preventing 90% of in-route breakdowns.”

Smooth Ride
Sitting by the side of the road waiting for a tow or a repair constitutes expensive downtime, but the wrong suspension can make being sidelined almost a relief compared with the discomfort of manhandling a truck with a miserable seat. To provide a smoother, more comfortable ride, Kenworth Truck Co. in Kirkland, WA, introduced new front and rear suspensions for its heavy- and medium-duty truck models at the Mid-America Trucking Show in March 2008. Applicable to the T800 typically used by solid waste handlers, the AG130 is a proprietary front-axle air-spring suspension and the AG400L tandem rear suspension offers a cost-effective solution as well as a smooth ride by using a trailing arm design.

The AG130 features a four-bag air spring configuration (as opposed to other systems that typically offer two). The additional air bags reduce road input and vibration, improving the ride. Roll stiffness is also improved for better handling and road feel. Twenty pounds lighter than traditional 12,000-pound-rated suspensions, it is compatible with disc brakes and is available in 12,000- and 13,200-pound ratings for several Class 8 models.

The AG400L, also compatible with disc brakes, is a 40,000-pound-rated highway rear-suspension for specific Kenworth Class 8 models. Its four-bag suspension supports fifth-wheel height as low as 42 inches and is a good choice when the articulation performance of the AG400 is not required.

In addition to introducing new suspensions, Kenworth, recipient of the 2007 J.D. Power and Associates awards for Highest in Customer Satisfaction for over-the-road, pickup and delivery, and vocational segment Class 8 trucks, has been focusing on other improvements. Jeff Parietti says the 2010 engine is at the top of the list. Besides legislative mandates and financial incentives for low-emissions engines, he says, fleet managers are “looking at green. They’re looking for products to save fuel and offer a green advantage of reducing emissions. For on-the-road, we’re working on a no-idle system, a medium-duty hybrid and regenerative braking for pickups and diesel trucks. That offers more payback for city use.”

Another area getting attention is the transmission. Kenworth’s T800 for such short-haul applications as solid waste fleets is now available with Allison 4000 and 4500 series automatic transmissions when specced with Cummins ISX engines not exceeding 1,650 foot-pounds. The new configurations provide the benefits of an automatic transmission while still meeting high horsepower requirements. The Allison 4000 and 4500 series transmissions offered are especially designed for rugged duty or highway truck operators that are seeking productivity gains, durability advances, and lower cost of ownership over the life of the truck. The transmissions also feature torque-converter technology to provide seamless power shifts, helping the vehicles work within the best duty-cycle speeds faster and more efficiently with better fuel efficiency and greater productivity.

Photo: Express Brake The Brake Alert provides a simple inspection tool for checking brake adjustment and brake life.

When it comes to transmission selection, Wood says it’s easy: It’s an automatic, and it’s an Allison. “They’re fully electronic—with lots of wires. The ECU has to connect with the ‘brain’ in the chassis. It requires a lot of coordination of wires in a constrained space. Engines run hotter, so they need bigger cooling packages. That means engine compartments ‘shrink.’ You can’t expose wires to solvents and the environment, so packaging is an issue, but we’re careful about where we place and move things.” The only real decision regarding transmissions, he adds, is size: small (weight saving) versus large (longer life).

Brakes are simultaneously an easy yet challenging decision. Driving the options are federal legislation on stopping distance, customer expectations on change intervals, safety and durability, but rarely fuel cost. “‘Green’ is driving engine selection, not brakes,” Wood insists.

The wide brake is taking hold of the industry. Wood says as recently as two years ago, the company sold only a few. Now, seven out of 10 trucks are equipped with wide brakes: 16.5 x 8.6, as compared with the previously typical 16.5 x 7. “They last longer before you have to change the linings; that reduces maintenance.” He says many companies are running two shifts, which translates to increased truck usage and places added pressure on the chassis and body. It also speeds up maintenance intervals. “We adapt to that and make different recommendations based on the application.”

Wide brakes also stop better, Wood claims. That’s more important than ever, in light of new stopping-distance laws being passed. “The new law could force all manufacturers to go to disc brakes [from cam brakes],” he predicts. “That would add expense due to a higher initial purchase price.” Peterbilt, however, counterbalances that with two years of testing that indicates disc brakes are durable and can last through extended maintenance intervals. The challenge, he notes, is that air disc brakes were designed for the trucking industry. “The refuse industry is not warm to the idea because of its history with disc brakes—but this is different.”

Another easy choice for Peterbilt involves the suspension. “We recommend the best,” Wood claims. “We use Hendrickson, the most popular.” Actually, Peterbilt offers a choice of 30 rear suspensions, including its own proprietary Peterbilt Air Trac. Since all suspensions work well in hot and cold climates, factors in determining the best suspension for each application include the type of truck body in question, because the truck body type dictates how much load is on the rear axle. “Air suspension gives the best ride. Since a rolloff is empty most of the time, with no payload, you need a sensitive suspension, or you’ll have a very stiff ride whenever it’s empty. Plus, the trucks last longer with air suspension.”

For a collection vehicle, Wood suggests a “vocational” suspension from Hendrickson, adding that “90% of the time, we choose Haulmaax for on- and off-road because it has the best possible ride. It does a pretty good job.”

To the Maax
Designed to be two-stage suspension, the Haulmaax from Woodridge, IL–based Hendrickson USA features a unique spring system that adjusts to the load. When the vehicle is empty, explains Jacob Madden, marketing segment manager, the Haulmaax system rides on bolster springs: four diagonally mounted rubber springs designed to absorb vertical road input and shocks fore and aft. When the vehicle is full, the bolster springs compress and increase in stiffness. Under higher loads, a high-density auxiliary spring engages for an added dimension of stability. The benefits include increased roll stability, better handling, and a lower center of gravity for additional stability. Since the center of gravity is higher when the load is heavier, Haulmaax provides the ideal combination of unloaded ride and loaded stability. It’s also designed to take corners in neighborhoods and city streets. The Ultra Rod torque rods control lateral forces, ensuring maximum lateral axle control for better cornering.

Hendrickson, which pioneered walking beam suspensions, deviated from the standard configuration that utilizes a fixed center-bushing pivot point, reducing routine maintenance on the Haulmaax. The Haulmaax system eliminates the center bushing on the walking beam by allowing the system to pivot on the bolster springs. Reducing the number of bushings cuts down on maintenance because there are fewer wear points—one advantage to consider when weighing life cycle costs. The Haulmaax system also has no lubrication requirements. No lube requirement means less maintenance. Less maintenance equals less downtime. “Our bushings are durable,” Madden reiterates.

Many factors go into choosing a suspension: durability (life cycle costs), stability, handling, weight (lighter weight means fewer vehicles and fewer drivers, because each vehicle can fill up more, carry more payload, and consolidate routes), and ride. The Haulmaax system was designed to be lightweight, saving up to 690 pounds over competitive suspensions without sacrificing durability or reliability. In addition, the Haulmaax’s improved ride reduces transfer of road vibration, which can result in fewer repairs to the cab, chassis, and body equipment.

It also provides a smoother ride for the operator. Madden indicates that fleet owners are interested in a better ride in order to retain drivers. “If the body without payload is heavy, ride isn’t as important, but these trucks operate under both conditions.” Not only do the collection vehicles operate empty and full, they drive on and off the road. “They drive into highly volatile dumps with uneven terrain,” Madden outlines, “so they need high-roll stability, high articulation. Our 17-inch diagonal articulation is the best in class.”

But mostly, these vehicles travel neighborhoods with lots of corners, making handling and roll stability extremely important. Another situation causing wear and tear is the stop-and-go operation unique to refuse vehicles. Using computer simulations and extensive testing programs, Hendrickson designs suspensions to equalize the weight transfer in braking conditions. “It’s a big issue,” Madden sums up.

Meeting all conditions isn’t easy, and there are different types of suspensions available for various applications. Hendrickson suspensions are offered as OEM options and are designed to be compatible with different truck manufacturers.

“All types [of suspensions] have their own place,” Madden concedes. You can choose a mechanical suspension spring, rubber or air, which provides a progressively better ride in a general sense. While most refuse trucks use mechanical or rubber-style suspensions, there has been a recent trend toward air systems, such as Hendrickson’s Primaax, that are designed for improved ride quality while providing the stability and off-road mobility required for vocational applications.

Primaax is a non-torque reactive system (for lurch) that provides better ride for long distance, high-speed applications. Its optimized geometry reduces suspension-induced driveline vibration, which in turn reduces wear and tear on the chassis and components. In an effort to expand on application approval, Hendrickson recently introduced the Primaax Ex for additional durability and performance in high center of gravity applications.

Tomorrow Today
Wood recognizes that “the world is automating, with fewer rear-loaders.” He believes it’s changing the nature of the trucks. “They’re sturdier, making 1,200 stops and starts per day. With today’s demand for high speed, there is also high usage of wear items.” Increased customer bases with the corresponding demand for faster service and more pickups, added to the challenge of a dirty environment and variable payloads, intensifies the stress on the equipment. Tight budgets, the high cost of new trucks, downtime, and repairs mean preventative maintenance has become a crucial part of every fleet’s routine.

Peterbilt has to stay current with all the changes, adjusting its chassis to accommodate developments and enhancements in manufacturers’ product lines. “Frame rails haven’t changed in 23 years,” Wood chuckles. “We adapt to their innovations.”

When Peterbilt adapts to those innovations, it strives to minimize the changes in design. “Consistent appearance and reliability are the keys to success,” Madden believes. It also means fewer parts to stock. Like its competitors, Peterbilt is currently designing its 2010 engine to comply with new regulations. While Madden confesses that it will change some things on the truck, he insists the truck will still look and behave like a Peterbilt. “New garbage trucks are very expensive. The Peterbilt 320 is a truck you can keep 15 years.” In today’s economy, that’s more important than ever.