Like the late comedian Rodney Dangerfield, transfer trailers “don’t get no respect.”
Transfer trailers are notorious for ugliness, being caked with mud and dirt, leaving a trash trail in their wake, chewing up the road surfaces on which they travel, running in unsafe condition, and maneuvering on the highways in a manner that causes accidents. Many people find the trailers odious—in a figurative sense and sometimes literally, as well, if the payload they’re hauling has been fermenting for a while.
Whether these complaints actually are justified depends on the individual situation. Though cost-cutting and sheer laziness may prompt some operators to run battered, grubby, overloaded, unsafe, poorly tarped transfer trailers, others strive to operate safely and responsibly.
“We want to be good neighbors, and we think we’re good people. We would not want it on our conscience if anyone got hurt,” says John Christofferson, sales and marketing manager for Trinity Trailer Manufacturing Inc. in Boise, ID.
“You also want the safest possible trailer you can put out there because if there’s an accident you’re going to get sued. In all our design meetings, the number-one thing we talk about is safety and the possible liability we would face if something went wrong when our trailers were on the highway. One bad accident caused by a poor design or a manufacturing defect has to be considered an ‘unneighborly’ act. If we are not good neighbors, we’re in big trouble.”
A Broad Umbrella
Safety is a broad umbrella that encompasses a wide variety of issues and adaptations. Federal law mandates certain minimum standards, which individual manufacturers are free to exceed.
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Photo: Pioneer Tarp |
| Tarps may be cotton, vinyl, nylon, or other material. |
Since 1986, the government has specified that tractor-trailer rigs must have antilock braking systems (ABSs). “The minimum federal requirement on a trailer is [an ABS on] one axle, but to enhance your braking capacity and keep tires from skidding, we recommend that you put ABSs on all the axles,” says Keith Limback of Manac Trailers in Saint-Georges, QB. He is the company’s US general sales manager, based in Freeport, PA.
An ABS is a computerized system of modulators and sensors that pulsates the brakes automatically if it determines that a wheel isn’t rolling while the vehicle is moving. Limback says the minimum system cost of $800 is built into a trailer’s base price, and adding ABSs to the rest of the trailer costs just $300 more.
“Before ABSs, we saw a lot of trailers come to a skidding stop,” he says. “That increases the braking distance and will flat-spot tires. If you hear a truck go by with a tire slapping, it’s got flat spots. The driver doesn’t hear it. He leaves it behind.”
The federal government also requires automatic slack adjusters, which adjust the distance between the brake pad and the brake drum. “As the pad wears, the adjuster moves the pad closer to the drum,” Limback says. “Some manufacturers have an indicator—a dial and a little arrow—that tells you the pad is worn. When the arrow exceeds its range, you know the pads need to be changed. Mechanics should look at the dial as part of their preventive-maintenance routine.”
Overadjustment of slack adjusters can occur, cautions Drew Larsen, general manager of Express Brake International Inc. in Ocala, FL. “If they aren’t performing properly, then the push rod can overtravel,” he says. “If you have an insufficient travel range left on your push rod, you’ll lose braking power.”
Red and white conspicuity tape must be applied to mark the sides of trailers. Mark Sabol, solid waste product manager at East Manufacturing Corp. in Randolph, OH, says his firm exceeds this requirement with a “retro-reflective” tape on the tarp bar running the entire length of its trailers.
Federal regulations for lighting include mid-trailer lights that incorporate turn signals. “If you’re following a truck and you swing out and want to pass, you can see the driver’s intention,” says Jon Keppel, refuse division manager for Redwood Reliance Sales Co. in Cotati, CA, a division of Reliance Trailer Manufacturing in Spokane, WA.
He predicts the federal government soon will require light-emitting diodes (LEDs) instead of bulb-type lamps. “You can see LEDs from yards and yards away,” he says. “They’re infinitely better. It’s such a small add-on—only a $100 cost differential—that it will become standard.”
Sabol says LEDs last longer than bulbs, burn brighter, and are more visible. “We protect all of our lights on the side and rear of the trailer so they’re less likely to be damaged in loading,” he says.
An underride device is like a railroad locomotive’s cowcatcher in reverse; it prevents a car that hits the back of a trailer from sliding under the trailer. “We spent thousands of dollars developing an underride that meets and exceeds all federal guidelines,” says Christofferson.
Innovation and Creativity
Some manufacturers offer safety features not covered by the federal requirements, such as Trinity’s Agri-Flex trailer made of high-tensile-strength carbon steel or stainless steel. “It gives us a 36-degree oscillation, 18 degrees on each side, built into the trailer,” Christofferson says. “If you’re under load and the trailer gets into a corner, one part of the trailer drops down. This design adds to its stability, and it will be less likely to roll over than a more rigid aluminum trailer that doesn’t flex.”
Wheels and hubs are another area. “Most trailers have the old-style ball-seat wheels,” Keppel says. “They require inner studs and outer nuts, which can loosen up and crack wheels. The hub-piloted wheel is just one stud and nut driven in. It centers the wheel and tends not to crack. It’s a better way.” Keppel predicts hub-piloted wheels soon will become a federal requirement.
East Manufacturing Corp. offers the East Elite wheel end system, a hub preassembled with the race and bearing. The assembly carries a five-year, 500,000-mile warranty. “It comes to us as a component,” says Sabol. “We use a locking nut that holds the bearing, so the bearing won’t come out of adjustment as easily. It makes for a safer trailer going down the road. Poorly adjusted bearings can wear out prematurely and fail.”
Most drum brakes have a crown-riveted brake shoe of carbon steel, but Express Brake International uses a patented stainless-steel shoe with no rivet holes. A stainless-steel retainer holds the lining in place. “We put more friction surface in contact with the drum and get about 9% better stopping out of the same total surface,” Larsen says. “It will last longer, stops faster, and is easier to reline, and its construction allows it to hold its geometry better than a riveted shoe.”
Mud flaps and splashguards minimize spray on nearby motorists’ car windows. The splashguard, a broomlike device made of rubber or plastic, hangs down about 2 inches inside the trailer’s wheel well, surrounding the exposed wheel and tire area. “Sometimes it’s called a hula skirt,” Keppel says.
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Photo: Reliance Trailer |
| Reliance Trailers' “Possum Belly” trailers are made of aircraft-grade aluminum. |
Rubber on the Road
Few things annoy motorists more than dodging the hunks of rubber that litter a highway in the wake of a catastrophic tire failure. Tire experts say such mishaps shouldn’t happen if the right tire is selected for the right application. The Tire and Rim Association Inc., based in Akron, OH, sets the technical standards for manufacturers of tires, rims, valves, and allied parts in the US, but a tire meeting the association’s standards for carrying a given load may not perform well under certain operating conditions.
“Over the years, Goodyear and other tire manufacturers have evolved specialty truck-tire lines, including mixed-service tires that will run on or off the highway,” says Tim Miller, a mechanical engineer who is a marketing communications manager at Goodyear Tire and Rubber Co. “They have a tread compound that will run cool as you go across the country on interstate highways, but it also allows them to go off the highway and withstand rocks and metal objects better than a highway tire would.”
Miller says these tires perform better in off-highway applications because they are chip- and chunk-resistant—formulated so rocks are less likely to cause damage—and the sidewalls are built to withstand side impacts.
“They cost a little more than a standard truck tire because they’re heavier and have more material,” he says. “An on-/off-highway tire typically costs about 20% more than its comparable highway counterpart of the same size, load range, et cetera. It has a considerably deeper tread, something like 22 thirty-seconds of an inch versus 14 thirty-seconds of an inch for a typical highway trailer tire. That’s almost 60% more tread.”
Goodyear also offers tires with DuraSeal Technology, a gel-like compound in the inner tire lining that seals punctures up to a one-quarter inch in diameter in the tread area. Tires with this compound can sustain multiple punctures and continue to operate without downtime for repairs.
Spread-Axle Trailers
Operators using spread-axle trailers should recognize that these vehicles have different operating characteristics than standard tandem trailers and need different kinds of tires, advises Guy Walenga, director of engineering and commercial products and technologies at Bridgestone Firestone Truck Tires North America LLC.
“Eight or 9 feet apart is the standard spread between tandem axles,” he explains. “When the spread is more, you load the vehicle accordingly as two single axles. Where a tandem trailer might be rated at 34,000 pounds, or 17,000 pounds per axle, a spread-axle trailer would be able to carry 40,000 pounds, or 20,000 pounds per axle.
“When you spread those two axles apart, the vehicle turns differently. One axle may have a dump valve, which allows you to take the load off that axle momentarily to do tight turning. When you carry that heavier load, make sure you’re speccing heavy-duty equipment that allows you to carry it—axles, springs, tires, et cetera. We build a particular tire to withstand the side forces you see in a spread-axle application, and it’s also a very good tire for getting off the road.”
The modern steel-belted radial tire is designed to be retreaded after its original tread has been used up. “Retreading is the original recycling program,” says Walenga. Before retreading a tire, an inspector will examine it and sometimes subject it to shearography—analysis in a vacuum chamber coupled to a video camera and a computer screen. “If anything is loose or broken inside the tire structure, the camera sees it move. Shearography sees things an inspector couldn’t find visually,” he says.
Tires selected for retreading are buffed with a special machine to remove all of the old tread. Then the new tread is applied with an adhesive, and the tire is cooked in a heated chamber to chemically bond the old casing, the adhesive, and the new tread.
“If done properly, a retreaded tire will work as well as a new tire,” Miller says. “The cost of a retread might be one-third the cost of a new tire—if you supply the casing—or two-thirds if you buy the whole tire.”
Getting Pressure Right
Whether a tire is new or a retread, maintaining proper inflation pressure will help prolong its working life. Underinflation makes tires run hotter, and heat separates the tread from the casing.
Several types of inflation systems exist. Link Manufacturing Ltd. in Sioux Center, IA, makes the Cat’s Eye, a system of hoses and gauges connecting the inner and outer tires on each set of dual wheels to an equalizer valve and an indicator that monitors their pressure. “When both tires are properly inflated, the eye closes. If there’s a decrease in pressure, the eye opens. If the decrease is more severe, the eye opens wider,” says Brent Kackley, Link’s marketing manager. “If there’s a problem, you have only a single filling point. Climbing underneath the sloppy, smelly trailer to check the inside tire isn’t that attractive. The system also equalizes the tire pressure between the two tires on the dual, helping dissipate heat from an underinflated tire into the other tire to decrease the risk of premature failure.”
Kackley says the duals on each side of an axle would have their own system, which is available with rubber or stainless-steel hoses. The gauges are preset in the factory to the customer’s required tire pressure. “Because it’s mechanical, there is no electrical interference with signals and electronic data,” Kackley says.
The Cat’s Eye is a good tool, Walenga says, but many people who use it don’t realize it requires maintenance. “Every time they change the tires on the dual, they should take the equalizer valve off, take it apart, clean it, put new O-rings in, reassemble it, and double-check the air lines attaching it to the tire,” he advises.
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Photo: Reliance Trailer |
| Front-loaders often are used in the loading of transfer trailers. |
Also available are electronic systems that monitor tire pressure and give the driver a dashboard readout so he knows where a problem exists. At the highest level of sophistication is a fully automated system, running off the air-brake compressor, that pipes air directly to the tires. “If you get a nail hole or a slow leak, the tire automatically refills and stays up to pressure, and you get a signal that you have a leak,” Walenga says. “The system is inexpensive and durable and can be fitted aftermarket. It’s designed to fit on any trailer, tire, and wheel.”
Miller says inflation pressure tends to be checked less often on trailer tires than on tractors’ steer and drive tires. “We’ve done fleet-inspection studies on a Saturday or Sunday when a lot of trucks are in,” he says. “The steer tires typically are very close to where they’re supposed to be, drive tires less, and trailers even less. Drivers care about steer tires. If a steer tire fails, they have a big problem. If they’re in a hurry or lazy, they may check just the steer tires. Drivers sometimes don’t even know they’ve lost a trailer tire. Even if one comes apart, he may not feel it happen or see it in his mirrors.”
Containment Options
Beyond safety, a major aspect of transfer trailers’ neighborliness entails containing the payload so it doesn’t blow out of the trailer in transit. The vast assortment of containment devices ranges from simplistic to sophisticated.
At one extreme are mesh nets or vinyl tarps unfurled atop the trash and tied down on the sides with rope or bungee cords. “Some operators have two people stationed on a platform on each side of the trailer to physically hand-roll the tarp,” says Robert Tuerk, retired owner of Aero Industries Inc. in Indianapolis, IN.
“That’s the cheapest form. It’s a third-world solution. It takes labor. You have people available whenever a truck comes in, but you hope those guys don’t fall off the trailer. If you get a workers’ compensation claim, it will be hell to pay.”
More complex tarping systems may deploy from front to back or side to side. They may be hand-cranked, electric, or hydraulic. Pioneer in North Oxford, MA, a subsidiary of Wastequip Inc. in Cleveland, OH, offers a heavy-duty system for open-top transfer trailers called Top Tarper. The patent-pending system deploys with a rotary actuator using gears. “Everybody powers the front lead bow,” says Lenny Brescia, president. “There’s a lot of flex in those systems, causing the lid to go for a ride. We utilize a common shaft down the length of the trailer, with four powered arms—one every 10 feet—for controlled covering and uncovering.”
Tarps may be cotton, nylon, vinyl, or some exotic fabric. “We have a tight-woven polyurethane mesh fabric made especially for our system,” says Bill Jones, vice president of sales and marketing for Mountain Tarp and Awning Inc. of Middlesboro, KY, another Wastequip subsidiary. “It has breathable holes. With solid vinyl on a 53-foot trailer, there are problems with the wind trying to pick it up.”
Transfer trailers can even be equipped with a rigid lid that clamps down atop the payload, but compressing the material to maximize the load can push out the sides of the trailer, causing an imperfect seal. To solve this problem, Sidewinder automated lid systems from Donovan Enterprises Inc. in Stuart, FL, have adjustable cables around the sides. At the touch of a switch, the Sidewinder covers or uncovers a load in 20 seconds. “The Sidewinder is the only automatic system that offers a rigid lid. We have a patented lid design,” says Brian Scott, product manager.
“Cable tension involves loosening a couple of nuts, tightening the cables, and adjusting the turnbuckles to get proper tension,” he says. “The cables that run down the side of the trailer opposite the hinges are a crucial component of the system. To keep a tight seal, cables should be checked weekly. If they are loose, they should be tightened.”
Although the Sidewinders cost 40%–50% more than Donovan’s manual systems, Scott says 90% of his customers prefer the automatic systems.
Trinity Trailer is developing an electric tarp because it is difficult to get and keep good employees, says Christofferson. “Operators are keeping older drivers longer on the job, and a lot of companies like to use women as drivers. One of the toughest things about pulling a trailer is tarping and untarping. An electric tarp will save on driver wear and tear.”
Each containment option involves tradeoffs in cost, weight, longevity of the covering material, complexity of the deployment technology, time required for deployment, and what is required of the driver.
“There’s not one tarp system every transfer operator can use,” says Glenn Ray, marketing/product development manager at Pulltarps Manufacturing in El Cajon, CA. “It depends what they’re hauling, how it’s loaded and unloaded, and what kind of trailer it is.”
Dripping Liquids
Containment concerns also extend to liquids dripping from a transfer trailer on the road. Most such trailers have seals that require maintenance and periodic replacement.
Sabol at East Manufacturing advises drivers to wipe the rear gate seal and the area around it with a rag before closing the gate after each unloading. “That keeps the glass slivers and abrasive fines of the load from impregnating themselves into the seal and causing it to wear prematurely,” he says.
On a live-floor trailer, rubber seals between the aluminum floor slats also wear over time. “They have a pretty long life based on usage,” says Limback at Manac Trailers. “We offer a one-year warranty, but it will last for three or more years before it needs rebuilding. That’s where maintenance comes in.”
Limback warns against dropping large, heavy objects on a live floor built for transfer operation. “After Hurricane Katrina, a lot of transient transfer-trailer operators went down to the Gulf Coast and put their trailers into demolition hauling. They wore terribly due to overloading when the weight restrictions were lifted for a time and because of impact damage—dropping large articles like a refrigerator or an engine block that you wouldn’t load at a transfer station.”
The products of SmithCo Manufacturing Inc. of Le Mars, IA, eliminate these seal problems. “We sell side-dump trailers,” says Rick Lawrence, national sales manager. “They’re watertight. They have no tailgate. The tub is a completely welded structure that is tipped up and sideways to deposit the payload to the side of the trailer. You don’t have leakage worries on the highway, and you don’t have a tailgate to worry about.”
Good Housekeeping
Transfer trailers by nature aren’t pretty, but keeping them free of grime and grunge can make them less unsightly. “The important thing for appearance is a little soap and water,” Limback says. “How often these trailers are pressure-washed varies greatly.”
Limback says smooth-side trailers are easier to clean than those with sheet-and-post construction. “The smooth-side has no rail at the bottom of the panels where liquid debris could accumulate, and it washes quicker. You don’t have to wash every post individually.
“Also, a smooth-side has a shinier appearance. Instead of a rolled sheet, it’s a hollow-core, extruded-aluminum panel that looks seamless from the outside and is tack-welded together on the inside. The smooth-side is 3% to 5% more expensive, but the appearance is better. Because the core is hollow, when you ding the material on the inside, you can’t see it from the outside. A sheet-and-post trailer shows battle scars.”
Keppel concedes that smooth-side trailers are easier to keep clean. But “I’ve seen operations that have sprayers for sheet-and-post trailers that seem to work just fine,” he says. “It’s a function of how sanitary your transfer station is.”
Keppel says the cleanliness and safety of any transfer-trailer operation “is a coordination between the trailer manufacturer and its products and the operators using the equipment for what it was designed for. To have a safe, reliable, cost-effective operation requires good-quality equipment and knowledgeable operators. Operational quality comes down from the highest part of management to the lowest guy cleaning up the shop. It’s a big team effort.”