Utility truck users demand lighter options without sacrificing capacity

April 2015 - By the time a commercial truck is loaded with equipment and material, shippers find they are over the legal weight limit just rolling off the lot. Truck builders are coming to realize, however, that aluminum offers an alternative to steel because its light heft doesn’t compromise its might.

Where steel was once the prevalent material used for medium- and heavy-duty trucks, Pride Bodies has made aluminum the predominant material choice for components it builds. Most recently, Pride Bodies introduced an aluminum workbench bumper, a novel idea in the sense that the alloy, up until now, was often avoided because it wasn’t viewed as able to withstand the same force and stresses as steel. 

Cambridge, Ontario-based Pride Bodies opened shop 16 years ago and began building aluminum truck bodies soon thereafter. “Our initial bodies were typical non-crane bodies but as time passed, customers made it clear they needed service trucks with an aluminum crane body,” recalls Andy deLivron, U.S. sales representative. “So over the last 10 years we’ve developed our aluminum bodies.” 

The company now provides all-aluminum trucks—with cranes manufactured by Next Hydraulics s.r.l., Italy—with a rated capacity of up to 60,000 foot-pounds. 

Cranes are rated in foot-pounds, or length multiplied by tip load. A crane that extends horizontally to 20 feet with a capacity of 1,200 is rated 24,000 foot-pounds. According to deLivron, when mounting a crane on a truck, the rated force must be transferred to the crane stabilizers and the truck frame. “That requires an engineered solution,” he says. 

“The largest cranes for service bodies are rated at approximately 67,000 foot-pounds.” Today, Pride Bodies builds aluminum bodies rated to 60,000 foot-pounds. Beyond that rating, the bodies are built of steel. 

“What we’ve found, as we’ve engineered our design, is aluminum isn’t a detriment; it’s an advantage in a lot of areas of the truck,” deLivron says. Aluminum surfaces fare better than steel outdoors facing the elements. Service truck bodies made with steel typically have a short life because road salts produce signs of rust in two to three years. They often must be replaced in only four years, he says. 

“Even though we use galvanneal, it is not good enough for many of our customers. We developed a design that is compatible with requirements of steel while offering the advantages of aluminum. You can’t tell the difference between our steel or aluminum bodies until you open the door,” deLivron explains, noting that steel interior is primed (to avoid rust and corrosion) and aluminum is not. 

Durability required

The service trucks Pride Bodies produces have to be able to accommodate the installation of a vise at the rear, welding, grinding and banging. It’s not surprising that Pride Bodies would take on the challenge of designing a durable aluminum bumper. “Eventually you run out of places to cut down on weight so, naturally, the bumper became the logical next step,” he says. “Again, we’re trying to increase payload so we knew that aluminum could save a considerable amount of weight in the rear bumper of the truck. Switching to aluminum resulted in a 200-pound savings,” deLivron says. 

“There is a cost to switch to aluminum, which equates to about $2.25 a pound saved. When you look at payload issues and fuel costs over the life of the vehicle, the savings are significant.”

According to deLivron, Pride Bodies’ competitors do not yet offer aluminum-built, crane-equipped vehicles with capacity beyond 20,000 foot-pounds. The company completed its aluminum 60,000 foot-pound crane body design last November. The first major order of high-capacity crane towers will roll off the production line in May 2015.  

Testing stability

Mounting a crane body on a truck chassis sounds simple but there is so much to consider. The chassis itself must be strong enough to handle torque loads applied to the chassis as well as the body. 

“We try to keep it simple for crane operators,” deLivron says. “When we design a body with a crane on it, we want the crane to have constant load capabilities in all quadrants. You want to have the right stabilizers when you pick up a load with the crane. Just because the crane is rated at a particular capacity doesn’t mean the entire truck is rated to handle the [same] load.” 

Pride Bodies tests each crane body and provides each customer with an engineer’s certification that the trucks are stable at the rated load in all quadrants. 

If a truck cannot handle applied stresses, Pride Bodies will know it before ever releasing it to the customer. According to deLivron, it’s not a given that every manufacturer tests for stability after the final assembly. “The [stability] test requires you to pick up a load at 118 percent of the capacity of the crane.” 

Conducted slowly and carefully, such testing allows Pride Bodies to make any needed adjustments.

“You slowly extend crane boom with a load at 118 percent of the crane capacity and observe how the outriggers and tires maintain contact with the ground and extend the boom until it reaches full extension and comes to a stop. This is done in a full 360-degree rotation from the base of the crane,” says deLivron. “What the engineer is observing is if there is a point when stabilizers or tires start losing contact with the ground—then you know you’re in a danger zone.”

An eye for change

It’s that sort of attention to detail that allows Pride Bodies to succeed. When engineering for durability for the body, for example, engineers discovered that an extruded aluminum floor instead of a steel diamond plate deck was no more difficult to fabricate than steel. It also proved it could be a solution for oil canning, a condition created by placing heavy loads on the floor of the body. Pride Bodies engineers found a solution to this issue by selecting one 1.125-inch-thick by 10-inch-wide extruded  aluminum interlocking flooring, then having the surface machined to offer a non-skid surface they call “tiger tooth decking.”

Utility truck buyers approach Pride Bodies with a specific set of problems they need resolved. A large distributor of construction equipment across Canada, as well as two of the largest railroads in Canada, needed to operate their work-truck fleets more cost effectively. One of the railroad companies needed to simultaneously handle two lengths of steel rail up to 6 inches wide by 19 feet long, recalls deLivron. 

The railroad had been purchasing Class 6 trucks with a gross vehicle weight rating (GVWR) of 28,500 pounds, then mounted on it a knuckle boom crane and boxes. “That Class 6 vehicle could handle a payload of 3,225 pounds. One stick of rail weights 1,660 pounds,” which means two exceed 3,320 pounds. “By the time tools were added, the truck was over the weight limit,” deLivron says.

The weight rating is important to the railroad because if the trucks are any heavier, drivers must have a different type of license. The trucks also become less cost effective. Pride Bodies engineers developed a body that increased the payload to 5,500 pounds with the capacity to haul two lengths of rail and tools while reducing the GVWR to 19,500 pounds. “The net result was a vehicle that was more efficient and less costly to purchase and operate,” deLivron says. “The savings was a result of using an aluminum body and a lightweight tensile steel service crane.”

Switching to aluminum bodies translates to a roughly 20 percent premium on the sticker price but that expense is quickly recouped through an extended lifespan and lower fuel consumption, especially once accessories are mounted on the truck. These service trucks are used in the construction, rail, water, sewer, gas, municipal and solid waste industries. The equipment and tools carried depend on the industry application, and varies by lengths and diameter of hoses, by the weight and diameter of cable reels and even lubricants that ride along—all of which present weight considerations.

“There are a lot of variables. Everyone has a slightly different need,” he explains. “While one truck might look like another when placed side by side, they might each have vastly different capabilities.”

The chassis remains steel but Pride Bodies constantly keeps abreast of the latest in technological and material developments. “Innovations coming from Ford with the 2016 aluminum cab F-650 and F-750 trucks are a big change,” deLivron says. “That’s a first for a mid-priced builder and we believe that’s just the beginning.” MM