Shedding pounds for payload
Some truck and trailer components, when removed from the vehicle or replaced with lighter-weight alternatives, can be worth their weight in gold. That is, if they can be removed without compromising strength and durability while converting any weight savings into payload.
Fleets that stand to benefit the most from spec’ing lightweight equipment run at their maximum gross combination weight more often than not. Take, for example, a liquid bulk hauler.
Chris Stadler, regional haul product marketing manager with Volvo Trucks North America, researched the value of lightweighting among bulk haulers when introducing the Optimized Series VNM [since replaced with the VNR]. He found a fuel hauler could increase profits by $95,000 per truck each year by increasing its payload a mere 320 lb. That’s based on hauling an extra 50 gallons of payload per trip, or 37,000 gallons a year, making three deliveries a day, 250 days a year. Diesel prices at the time of that calculation were about the same as they are today.
And there are lots of ways to find a 320 lb. weight reduction. That could be why bulk haulers are the most willing to invest in lighter-weight equipment. The North American Council for Freight Efficiency (NACFE) published a 2021 Confidence Report on lightweighting, and found that bulk carriers will shell out an average of $6-$11 up front for every pound of weight saved. By comparison, dry van fleets will only pay between $0 and $5 per pound.
This makes sense when you consider bulk haulers almost always travel at their gross vehicle weight limit for at least a portion of their routes.
“They look at whatever they can do in terms of lessening their weight,” Stadler said of bulk haulers.
Refrigerated carriers are another candidate for lightweighting, as they gross out before cubing out [maximize payload before filling the trailer] on about 10% of their trips. Together, those two segments account for about 12% of the trucks on the road, NACFE reports. But that means about 88% of the trucks on the road have little to gain from lightweighting.
Do it for the right reason
Andrew Halonen is a lightweighting consultant with Michigan-based Mayflower Consulting. He says fleets should only consider trimming weight if it can be converted into payload, not to reduce fuel consumption.
“It’s more about carrying more stuff than fuel consumption,” he said. “If your focus is fuel prices, the bigger lever is something like aerodynamics. You’d have to save hundreds of pounds to notice it on your fuel bill.”
Ironically, if fuel consumption reductions are your end goal, you’re better served putting weight onto the truck and trailer in the form of aerodynamic fairings, anti-idling devices and other fuel-saving technologies. A regional bulk hauler may see little benefit from aero, but a longhaul food and beverage carrier such as the fictitious one illustrated above may have to strike a balance between reducing weight where possible, while also installing aerodynamic equipment.
NACFE reports that a 1,000 lb. weight reduction will translate to a mere 0.5%-0.6% fuel economy improvement – barely noticeable compared to the savings generated by aerodynamic fairings and devices.
Many lighter-weight options, such as smaller displacement engines, cost less than their beefier alternative while at the same time trimming hundreds of pounds. Stadler said a customer can save more than 300 lb. going from a 13-liter engine to an 11-liter. But other alternatives, such as aluminum wheels, will cost more to purchase. That’s where a cost-benefit analysis comes in.
“Everybody says they want the next thing, then they see the next thing costs more and it’s ‘Woah, let’s go back to what we’ve always been doing’,” says Halonen. “There has to be a financial incentive.”
He urges fleets to look for lightweight alternatives that offer additional benefits, above and beyond the weight reduction.
“If all you are bringing is lightweighting, usually that switch is not worth it,” he said, adding side benefits such as the corrosion resistance of alternative materials should also be considered. “I thought everybody was buying aluminum wheels because of the weight, but a lot of fleets say it became less about weight. They look awesome and will continue to look awesome because of their nice, robust coating and they buy them because they attract drivers, have good resale value and are low maintenance.”
In that case, the 270 lb. of weight that can be taken off a tractor by converting from steel to aluminum wheels is gravy.
What’s driving lightweighting?
Since only about 12% of trucks on the road run at their maximum payloads the majority of the time, why do industry suppliers place such an emphasis on celebrating every pound taken out of their products?
It may be because the industry has been fighting an uphill battle over the last decade when it comes to weight. NACFE reports that emissions regulations, fuel economy features and driver amenities have added about 1,000 lb. to a tractor over the past decade. Fleets competing for skilled drivers find large, condo-style sleepers loaded with all the comforts of home are needed to attract and retain those drivers.
Meanwhile, the products shipped in van and reefer trailers are becoming denser as manufacturers focus on new packaging materials and techniques that allow them to pack more product into a single load. For bulk haulers, where any weight savings can usually be converted to payload, the spec’ing mindset has changed, according to Mike Trianos, vice-president – fleet maintenance and procurement with Transcourt Tank Leasing.
“Rather than looking at what they need to haul a certain product, they’re looking at what they don’t need on the trailer,” he said.
For example, can they make arrangements with a reliable tire supplier along their routes to ensure quick roadside replacements, doing away with the heavy spare tire, tire carrier and associated mounting brackets?
When it comes to material selection, tanker carriers seek weight savings in the form of aluminum wheels and hubs, aluminum or plastic fenders, and when possible, an aluminum frame and barrel.
“Using lighter materials or thinner gauge metals can save weight, but structural integrity should always take precedence,” Trianos cautions. “The last thing you want is a trailer that fails under stressful conditions.”
For that reason, he advises against seeking weight savings on structural components such as frames and dolly leg supports. Stadler says the same is true on the truck.
“The aluminum frame went away, and in its place innovations in steel frames are coming down the pike that can still save hundreds of pounds but they’re steel, they’re stiff, they are good with fatigue.”Andrew Halonen, Mayflower Consulting
“When it comes to some liquid bulk hauling, there’s a lot of twisting that goes on because of the sloshing effect in the trailer, especially if it’s unbaffled,” he said. “That kind of movement on a chassis can cause some strain. Even if you go with aluminum crossmembers you want to make sure they’re robust enough to take the twisting effect you might have with that type of payload.”
Some weight-saving options have quietly vanished from the market, when early promise faded under real world stresses. Halonen cites aluminum truck frames as an example.
“The aluminum frame went away,” he said, noting some fleets complained of flexing and fatigue, and one even removed the frame and put a steel one back in its place before resale. “There had to be a lot of costs associated with that. The aluminum frame went away, and in its place innovations in steel frames are coming down the pike that can still save hundreds of pounds but they’re steel, they’re stiff, they are good with fatigue.”
More recently, OEMs are experimenting with lighterweight cross-members. Stadler said aluminum crossmembers save about 50 lb. each compared to steel. Volvo is also experimenting with a design featuring a crossmember that doubles as an air tank.
When it comes to future designs, Trianos feels the tank trailer industry will be hard pressed to find further opportunities for weight reduction. The low-hanging fruit has all been harvested.
“Manufacturers have pushed the limits of their engineering departments over the years to find ways to save weight without compromising the strength and integrity of the trailers, and I believe that manufacturers have reached their limit,” he said.
But Halonen feels further weight savings on the tractor can, and must, be achieved. That’s because electric powertrains that promise zero-emissions transport will add about 2,500-5,000 lb. to the vehicle, potentially eating into payload fleets can’t afford to sacrifice. The automotive industry, which is further advanced in the electric vehicle space, has found creative ways to reduce vehicle weight, which truck manufacturers have yet to exploit.
“There are some technologies we have seen in the automotive world that don’t appear to be happening in the commercial vehicle space,” Halonen said. “Under the instrument panel the structural baseline is steel, but in automotive we see a lot of aluminum extrusions. That’s something nobody will notice. They do that every day in automotive, it’s not rocket science.”
Some more advanced weight-saving options are being explored by various OEMs as part of the U.S. Department of Energy-funded SuperTruck projects. One of the most interesting is a film just 50 microns thick that can be applied in place of traditional paint, including base coat, main coat and clear coat. The ‘paint’ film, used today in the racing world, can save about 44 lb. on a day cab tractor and 147 lb. on a 53-ft. trailer.
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