The Knapheide Manufacturing Company now builds aluminum service bodies. Using aluminum instead of steel is one of the most common lightweighting strategies.Photo: The Knapheide manufacturing Company
“Lightweighting” has become recurring talking point in the truck world. But what are its benefits and how can that talk be turned into action?
“There’s a real market drive to try and take weight out,” said Chris Weiss, vice-president of engineering at The Knapheide Manufacturing Company, whose colleague Justin Steel was scheduled to give a presentation on this subject at the 2019 Work Truck Show in Indianapolis as this edition was going to press. “That’s for a variety of reasons. A lot of times you might think, ‘Oh, well, they’re trying to save fuel.’ Of course, that’s one possibility that they’re trying to save a little bit of fuel economy. If you know much about the work truck industry, that’s usually not first in their mind. Especially where the gas prices are cheap, that’s not always the primary driver.”
Weiss notes that while fuel savings can be a motivating factor for lightweighting, particularly in larger fleets with many vehicles, regulatory issues can also be a driver.
“There’s a very distinct cliff of those regulations when a vehicle is over 10,000 pounds versus 10,000 and under,” Weiss says. “So there’s a huge demand, especially in the service body industry, to try and fit as much as possible on that Class 2 vehicle that doesn’t go above 10,000 gross vehicle weight.”
No one-size-fits-all solution
Jon LeFaive, sales engineering manager for Dakota Bodies, was also on the speakers list of the Work Truck Show presentation, titled “Weight Reduction — Every Pound Counts.” He notes that lightweighting can be looked at from various perspectives — vehicle efficiency, wear and tear, and loading the engine more, for example. Every mechanical component of the truck is working harder to haul more weight. So if you can reduce that, it’s affecting the life cycle of a vehicle. But the specific needs of each operator can be different.
“Looking at it from an economic standpoint, and it makes more sense for your fleet to spend less money on a vehicle and just load it up more, then that’s a return on investment that needs to be looked at on a case by case basis,” LeFaive says. “There’s not really a one size fits all. To me, every situation is somewhat unique.”
LeFaive says modern equipment like tube lasers have made it easier and more economical for producers to take a C channel or an I-beam and lightweight it by removing material around the neutral axis of the structural profile. Or, if you’re forming those parts out of sheet metal, they can be designed that way from the beginning.
“Now, you can certainly switch to a different material and gain even more, but in the case of switching from steel to aluminum, you’re going to pay a premium for that other material because it costs more to get the job done with that material,” LeFaive says. “But sometimes it’s not necessarily needed if you can redesign using the original material. Just redesign with lightweighting in mind.”
Switching materials
Switching to aluminum is one of the most common lightweighting strategies. But Weiss notes that it’s not just as simple as changing the materials used, because aluminum isn’t as strong as steel. Changing from steel to aluminum required Knapheide’s engineers to redesign many of the components they work with.
“We engineered it so that we have the same or greater strength of our steel products,” Weiss says. “It took a lot of work to do that. Our customers want to do the same amount of work. For whatever reason you want a lightweight, if that’s fuel economy, payload optimization, driver compliance, whatever it is, you still gotta do the same amount of work. So you gotta have a body that’s a strong, if not stronger, than the steel version.”
Aluminum is the most common material to replace steel, but far from the only one. One of
A vehicle over 10,000 pounds is subject to stronger regulations than those below, so finding alternate materials to create bulkheads and other parts can be essential to keeping overall weight down.Photo: The Knapheide Manufacturing Company
Knapheide’s enclosed service bodies had a walk-through bulkhead in it, which was originally made of steel. However, the company had experience using acrylonitrile butadiene styrene (ABS), a thermoplastic polymer, and designed an ABS partition that saved hundreds of pounds. Thermoplastic olefin (TPO), often found in car bumpers, is also commonly used for constructing fender skirts and the light.
Effects on drivers
Driver compliance is another topical issue. It may not seem obvious on the surface how changing a vehicle’s weight can affect driver compliance. But, as Weiss notes earlier, there are more restrictions and regulations for vehicles over the 10,000 pounds threshold. LeFaive also points to other compliance issues as simple as frontal area restrictions.
“Maybe you got somebody that’s got an F-250 pickup and they want a great big super structure on there. Say they’ve got somebody that’s six-foot-eight in their fleet and they want them to be able to stand up inside,” LeFaive says. “You might not be able to do that and still maintain compliance, just because everybody has to adhere to that frontal area restriction for that specific OEM and the make and model of that vehicle.”
There is no one-size-fits all approach for lightweighting, LeFaive observes. Removing 500 pounds from a class 6, 7, or 8 truck won’t make much difference to fuel economy, but it could make a significant difference on a smaller pickup truck.
— Matt Jones
Matt Jones is a freelance writer based in Fredericton, N.B.