The specifications for refuse-collection trucks can make for incongruous "recipes" at times.
Manufacturers of refuse-collection bodies, chassis, running gear, and accessories tell horror stories about receiving specifications for trucks that require major modifications to make their components fit together, and others that can’t be built at all because the specified components are totally incompatible.
Sometimes the problems arise from a customer specifying a chassis and a body with components that compete for space on the vehicle. Richard Hugger, sales engineering manager for chassis-maker Crane Carrier Co., tells of a chassis his firm built with a forward-mounted battery box. The body company needed that location for something else, so its staff moved the battery behind the drive axle.
“The battery cables were 10 feet too short,” Hugger says. “They spliced extensions to the cables, but that created too much resistance, causing the battery cable to overheat and short out, causing a small fire. The customer believed the chassis was built with spliced cables, so he requested warranty reimbursement.”
Houston Ratledge, a product manager for body manufacturer Heil Environmental Industries Ltd., tells a similar tale. “A customer sends in a chassis with a particular transmission, and I don’t have adequate space to get a PTO [power takeoff] and pump combination on that chassis,” he laments. “When I point out that he asked for an incompatible body-chassis combination, the customer confesses that he thought manufacturer A was going to get the business, but manufacturer B submitted the low bid.”
Hugger says choosing between a transmission PTO or a front crankshaft PTO sometimes creates problems. A transmission PTO can put an extra load on a transmission and cause additional wear on the gears when it engages and disengages, whereas a crankshaft PTO runs constantly off the engine. “People may specify a transmission PTO because when they go out for bid, they don’t know which body is going to be bid, and a transmission PTO fits on all trucks regardless of who the body manufacturer is,” Hugger says.
Crane, however, prefers a front crankshaft PTO. “Our engine is set back under the cab, and the body hydraulic pump is direct-driven off the crankshaft without a protrusion through the grille or front bumper,” Hugger says. “A lot of our competitors’ chassis have a radiator right at the front grille, so the pump sticks out in front of the truck, adding length and exposing the pump to potential hazards. Some of them run a drive shaft from the crankshaft of the engine through a hole in the radiator to a pump in front of the radiator. Drive-shaft problems can take out a radiator, and that can get expensive.”
Regional Issues
Gerry Remus, vocational market segment manager for suspension manufacturer Hendrickson International Corp., says capacity and suspension specifications appropriate for the eastern United States aren’t always ideal for the West Coast, and vice versa. “Some tweaking is necessary to customize for local and regional weight laws,” he says. “In the east, you typically need a 46,000-pound or 52,000-pound rear suspension. In California a lot of them are 40,000 pounds, and the Department of Transportation is very active in monitoring overweight.
“Using a 40,000-pound suspension in a 46,000-pound or 52,000-pound application can be a disaster. An underspecified suspension leads to higher operating costs and higher life-cycle costs because its components are more susceptible to premature wear.”
Overspecification also causes problems. “If a front axle and suspension are overspecified to a 20,000-pound capacity when a truck needs only 16,000 or 18,000 pounds, you don’t get a very good ride,” Remus says. “The extra steel leaf springs don’t have a chance to deflect and provide a soft ride. Because they aren’t seeing the loads they’re supposed to have, the ride quality is poor and uncomfortable.”
Sometimes a fleet customer operating in multiple regions inadvertently specifies a truck for one region that should have gone to another. Sometimes larger companies acquire their competition and need to provide trucks quickly at the new location. Trucks are often shuttled between regions to save the expense of buying new equipment, but they don’t always have the right suspension. Remus says retrofitting the right suspension onto a truck may involve changing the axles, brakes, and tires as well, and can cost thousands of dollars.
Silent Drive Inc. offers 10 basic models of air-ride suspension for lift axles in the waste industry, but it also creates specialized equipment to meet a body manufacturer’s particular needs.
“For Loadmaster,” says Reese Kelch, Silent Drive’s national sales manager, “we created a lift axle for rear-load bodies—a specialized suspension that nobody else would use on a truck. It’s for trucks going into Michigan, Minnesota, and Wisconsin, where frost laws protect their highways by severely limiting the weight per axle. They wanted to get the axle back as far as possible, and they trimmed the hopper sides down to accommodate a lift axle back there. We created a lift axle to accommodate those parameters.”
Dale Puhrmann, western regional manager of sales and marketing for Link Manufacturing Ltd., covers 13 western states, each of which interprets the federal bridge laws differently. “The first question is what’s acceptable in my community,” he says. “Two states in my territory—Colorado and New Mexico—use very few lift axles, and in California the laws governing lift axles are difficult to understand so people tend to shy away from them. In the Pacific Northwest, multitudes of trucks have lift axles.”
Options And Accessories
Body manufacturer McNeilus Companies Inc., cooperates with selected chassis manufacturers to offer packages tailored to regional quirks. “If a customer sends us a chassis, we must make sure it will fulfill the requirements of a refuse vehicle,” says Jeffry Swertfeger, director of marketing communications for McNeilus.
“In a perfect world, our customers would send us chassis that were always specified correctly, based upon the jobs these chassis need to perform. The reality is that this isn’t necessarily the case, and you sometimes have chassis ordered by entities that are not familiar with the tasks these vehicles need to accomplish. When low bid is a factor, we need to pay particular attention to the chassis choice to ensure the vehicle has been configured correctly for a refuse body. Moving fuel tanks, cross-members, air dryers, and sliding axles can be a very expensive oversight for the customer. In extreme cases we may even have to reject a chassis.”
Some manufacturers are introducing interactive online forms that help specification writers choose the appropriate components for trucks being created for particular applications. Industrial Lifters sells 25 truck-mounted tipper models in nine series for rear-loaders, and 39 tipper models in 13 series for side-loaders.
“We recently created on our Web site a request-for-quotation page for truck-mounted tippers,” says Alan Charky, the firm’s sales and marketing director. “It helps you figure out what model is best suited to your needs, which is half the job. The page educates people about the different options and the important criteria that manufacturers use to determine what the application is. Once you decide what you want, the Web page invites you to submit that information and request a no-obligation quote. We’ll reply by fax or e-mail within 24 hours.”
Nuances Of Weight
Chalmers Suspensions International Inc. sells a suspension system built around a hollow self-dampening rubber spring. “It offers full freedom of articulation, both parallel and diagonal,” says Livio Luchini, manager of sales administration. “Without leaf springs or airbags to replace, it has very low maintenance and reduces maintenance to the vehicle itself.”
Luchini says some fleet managers include Chalmers among two or three suspension options in their specifications, but they can be misled if the specifications are based on actual rather than installed weight. “In many cases,” Luchini says, “Brand X has a suspension that’s 20 pounds lighter than ours. That’s the actual suspension—but his installed weight with extra cross-members may be heavier than ours.”
Luchini says a Chalmers suspension “is basically compatible with any type of truck chassis, though the space between tandem axles may be a limiting factor. Canada has 60-inch to 72-inch spreads, but in the US every state is different. Ninety-five percent of the Chalmers suspensions in the US run on 54-inch spreads.”
Sometimes, Luchini says, the body type or the mounting location required for other equipment may affect where the suspension goes. “We can tuck the suspension to the back end of the vehicle frame for a single rear axle and even for a tandem,” he says. “We haven’t had an instance where someone says he can’t put a body on a chassis equipped with Chalmers suspensions. The body companies can build the body around the chassis, though it might be a deviation for them to get their body to work on that particular chassis.”
Wheelbase Errors Common
Wheelbase errors are among the most common specification problems, the manufacturers say. “There are legal implications if a driver loses control of a refuse-collection vehicle because of bad loading conditions and runs over a 7-year-old getting off a school bus,” Ratledge observes.
If the vehicle needs an altered wheelbase, Heil may be able to fix it. “We have a facility at our plant,” Ratledge says. “We can dismount the rear suspension from its current location on the chassis, reposition it as required, redrill the frame for that new position, and rebolt the suspension to the frame at its new position. Then we can mount the body on the chassis—but there is a fee for changing the wheelbase. It could be $1,600 to shorten or $2,800 to lengthen.
“If the customer acknowledges he screwed up, he has to pay the fee. If our distributor screwed up, then he has to pay it. We have been known to screw up, and then we absorb the cost.”
For body manufacturer Labrie Equipment Ltd., specification issues may arise with chassis frames that will be modified to make the Expert 2000 Helping Hand, a hybrid side-loading truck that accommodates both manual and automated refuse collection. Its loading hopper is just 44 inches high. The operator has automation to tip compatible carts, and he can manually load light bulk waste, such as empty appliance cartons.
Labrie’s national sales manager, Victor “Skip” Berg, explains that to build an Expert 2000 Helping Hand, Labrie cuts the chassis frame in half behind the cab and inserts a drop—an S bend—creating a depression in the frame into which the hopper fits when the body is built.
“We won’t drop a single frame,” Berg notes. “Frame rails on trucks are made of C channels. Most have dual nested channels, but some use a single heavy-duty channel. We would hope to catch that during the specification process, but even if that spec goes out on the street, a reliable manufacturer would take exception to it and bid for a double frame rather than a single frame.
“Most often we find ourselves taking exception to specifications not because they’re impossible but because they’re not the best for the customer. If it’s an old technology, we’ll give them the improvement. As a responsible bidder, we’re not always the cheapest, but we try to provide the best overall experience.”
Specification Styles
Autocar LLC makes cab-over chassis for refuse-collection trucks and has an exclusive agreement with Cummins Power Generation Inc. to supply engines. “If someone specifies Caterpillar engines, we don’t have much of a chance,” concedes Tom Vatter, Autocar’s vice president of sales and marketing.
“With the new 2007 emissions requirements coming up, we felt Cummins had the best solutions and track record for this next threshold. We have a full line of Cummins diesels—three different engines, ranging from 8.3 to 11 liters, and nine horsepower ratings from 285 hp to 385 hp across those three engines—and two different natural-gas engines. These engines have the potential to perform any application in the refuse industry.”
This example illustrates a crucial stylistic difference. Some specification writers state what they want in broad generic terms and then add “or equivalent”—in effect opening the bidding process to almost anything in the marketplace. Others specify with rigorous precision.
“Some military specs try to describe something as though they’re inventing it,” says Mark Caton, fleet systems manager in the division of fleet services for the Lexington-Fayette Urban County Government in Lexington, KY. “Some folks will write a bid spec that’s very proprietary to make sure they get exactly what they want, but they pay a super-high price for it because of the way their specs are written.”
Caton tries to stake out a middle ground. “I look at what’s available in the marketplace,” he says, “and narrow down the field of available bodies to a handful I feel will serve us the best from a reliability and maintenance standpoint. Then I attempt to describe certain attributes of the truck, using minimum requirements for the thickness and tensile strength of the steel used in various parts of the truck. By eliminating products I feel are somewhat inferior, I force any potential bidder to bid products that will meet these descriptions.”
A Systematic Process
Ratledge has a systematic process for analyzing the appropriateness of a prospective customer’s specifications. “Some entity has determined that he’s going to pick up garbage in a very basic body saddled onto a mule that we’ll call a chassis,” he says. “Let’s say the customer has determined that he needs to pick up 15 tons of municipal solid waste a day.”
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| Body type can affect mounting suspension. |
The customer typically knows whether he wants a front-loader, a rear-loader, or an automated side-loader, and Ratledge inquires about the route layout. “For a city with an abundance of cul-de-sacs, you would specify a chassis with the shortest possible wheelbase to make the turning diameter as small as possible,” he says. “Most everybody has a wheel cut of 45 degrees, but one or two chassis manufacturers go up to 47 or 48 degrees so they can turn in a smaller cul-de-sac.”
Then Ratledge calculates the load distribution on a theoretical body and chassis of the desired type. Using the known chassis and body weight and the approximate payload in this example, he determines that the truck will require a chassis with a 12,000-pound front axle and a 23,000-pound rear axle. Given that information, he consults a chart that illustrates the minimum resisting bending moment—a multiple of the frame section modulus (which defines the geometric boundaries of a cross section) multiplied by the yield strength of the steel. Most truck frames are made of steel with a yield strength of 100,000 to 110,000 psi, which means that much tension or compression would be required to cause deformation of the material.
The axles specified must be heavy enough to support the load, and the brakes are rated in conjunction with the axles. “Some manufacturers offer special brake options, but in many cases that has to do more with brake-lining composition than sizing,” Ratledge says.
To illustrate the process, Ratledge calculated load distributions for two rear-load trucks with the same chassis, cab-to-axle dimension (the distance from the back of the cab to the center line of a single rear axle), and afterframe (the projection of the frame rearward from the center line of the rear axle). The conventional cab model has a 200-inch wheelbase; the cab-over model has a 160-inch wheelbase yet holds an extra 1,500 pounds (14.6%) of payload.
“The cab-over is better for cul-de-sacs and tight turns,” Ratledge says. “Of course, the driver of a cab-over gets exercise jumping up and down—but in a lot of cities the driver never exits the cab. Two swampers load the tailgate.”
On an average day, Ratledge calculates five or six load distributions; each takes him about five minutes once all the data on the chassis-component ratings are established. The load distribution will be computerized shortly to simplify the process for everyone. This involves considerable programming to encompass all of the variables for about 40 different bodies.
“It’s not major math,” he says of the calculations, “but the irony is it intimidates people so much that they don’t want to look at anything except the bottom line: the loads on the front and rear axle. Hopefully, the computerized program will remove that fear.”
Torque And Horsepower
After calculating the load distribution, Ratledge determines the engine torque and horsepower necessary to power the truck. Torque is a turning, twisting, or rotating force; horsepower is a theoretical value derived from torque. To calculate the horsepower produced by 300 foot-pounds of torque developed at 2,000 rpm (revolutions per minute), multiply 300 by 2000 and divide the result (600,000) by the constant 5,252, which gives 114.24 horsepower.
“Since a refuse truck needs power for a hydraulic pump, some applications demand as much as 360 foot-pounds of torque net to the hydraulic-pump input shaft at idle. Depending on the engine manufacturer, idle ranges from 650 rpm to 800 rpm,” Ratledge says.
“Generally the toughest applications at idle are a front-loader or an automated side-loader. They require a larger pump that delivers more gallons per minute because the hydraulic system has more work to do.”
With respect to suspension, Ratledge says in most applications an automated side-loader with a 40,000-pound rear axle and 40,000-pound rear springs would be acceptable, and so would a rear-loader with tandem axles rated at 40,000 pounds. A 32-cubic-yard rear-loader outfitted with high-capacity container lifting devices should be equipped with a 46,000-pound rear. Rear-loaders with a single rear axle, however, need springs rated about 30% higher than the axle rating because they have an “exaggerated” load to the rear. “During the early part of a route when the rear of the body is loaded the most, you want to prevent severe sagging of the springs and limit the swaying of the body caused by the vehicle’s overturning moment. Typically, I like to see a 30,000-pound spring pack on a 23,000-pound single rear and a 34,000-pound spring pack on a 26,000-pound single rear.”
If any aspect of a refuse-truck specification approaches a universal standard, it’s the selection of Allison transmissions from General Motors Corp. “Allison must control 98% of the market in trucks in the US,” says Ratledge. “It is the elephant in the room. For the larger refuse compactors, its 3000 and 4000 series are the ones with adequate torque and horsepower ratings.”
Ratledge says a refuse truck should have an automatic transmission “If for no other reason than it’s getting difficult to find drivers who have shifted a manual transmission. Training somebody to do that isn’t always easy.”
Consultation And Collaboration
Manufacturers complain that some specification writers, especially in municipalities, compile from multiple sources a list of desired components and features with no assurance that they will work together. Dealers and distributors are a manufacturer’s first line of defense against incongruities and incompatibilities. When orders are placed, they are scrutinized at the factory before anything gets built.
“Communication is the key,” says Kelch at Silent Drive. “Everybody needs a clear conception of the end product. Specification writers have to figure out what their need is, then communicate with the manufacturers to see if what they need can be created.”
“Our direct-sales team consists of refuse specialists who are chassis-and-body spec savvy,” says Swertfeger at McNeilus. “We work closely with the customer to specify an appropriate vehicle for his specific application and to make sure the body works flawlessly with the chassis. That’s the goal.
“When we have a new customer who hasn’t done this before, we pay a lot of attention to his hauling situation, surrounding him with the appropriate technical people. We work with him as a partner in that process to make sure he orders exactly what he needs.”
Many specification writers—municipal and private alike—rely on their past experience to create a specification format. “That works as long as the equipment doesn’t change, the products continue to be available, and the companies stay in business,” notes Hugger at Crane Carrier.
Puhrmann at Link Manufacturing says people who specify based solely on past market information feel safe because they deal with known quantities. “Instead of being on the leading edge of technology, they sit back and let someone else use the product for a while, but they do that to their detriment,” he warns. “It prevents them from taking advantage of the newest technologies. By not looking at new technologies, customers may pass up something that may be beneficial to them.”