Weight, and what we're willing to pay to shed pounds, is relative. Tare isn't quite as critical to a typical truckload carrier as it is to a bulk or beverage hauler, but fuel costs are forcing even the modestly weight-sensitive over-the-road crowd to re-examine their specs.

Federal Highway Administration estimates suggest the average over-the road truck grosses slightly less than 70,000 pounds. That's not universal, of course, and even with lighter payloads, axle weight can still be a concern - though maybe not the biggest concern anymore.

"Historically, fuel savings derived from expensive weight reduction strategies were insignificant," explains Mark Wagner, vice president and general manager of ConMet. "Most of the attention focused on chassis weight reduction for capacity gains." But with the price of diesel near $5 a gallon, that's changing.

In its Recommended Practice 1112, the Technology and Maintenance Council of the American Trucking Associations offers a "fuel improvement factor" of 0.0375 mpg per 1,000 pounds for trucks in the 60,000- to 80,000-GVW range. The factor is used in calculating overall weight-related cost savings potential with fuel cost, mileage, and time as variables.

"At 40 to 90 cents per year per pound of weight saved in fuel costs with $5-a-gallon diesel, and with savings increasing with mileage, the high-milers can really save," Wagner notes.

To the highly weight-sensitive bulk crowd, pounds saved means dollars in the bank, plain and simple. But they, too, can save on the backhaul. Normally running empty half the time, tank and dump operators gain a fuel cost advantage too. Lighter tare means less cost moving the truck over those non-revenue-producing deadhead miles.

But there's a growing concern about the EPA-inspired weight gains we've experienced since October 2002. As the sidebar on the next page, "Trucking's 800-Pound Gorilla," explains, adding all that emissions-related hardware to the chassis is cutting steer axles out of the payload-bearing picture. With EPA 2010 fast approaching, chassis weight will become even more of an issue.

What Gets Cut

It's remarkable what you can accomplish when you put your mind to it. Coover Trucking in Erie, Kan., hauls cement in bulk tanks. Owner Dave Coover is very sensitive about weight; to him, whacking 1,000 pounds from the truck means a net revenue gain of a nickel a mile. Five years ago, he was happy with a 26-ton payload, but working with his suppliers, and trimming everywhere it made sense to trim, he has increased his carrying capacity to 27.5 tons.

His Peterbilt Model 365 tractors, with 120 gallons of fuel and a pneumatic unloading pump on board, tip the scales at just 16,300 pounds. The basic spec includes a 410-horsepower Cummins ISM, a Fuller 10-speed transmission, 370:1 rears, Dana axles with Peterbilt Low Air leaf suspension, 22.5-inch wheels with low-profile tires, a single 120-gallon fuel tank, a fixed fifth wheel, Centrifuse brake drums, and a 36-inch flat-top sleeper. The door weight stamped on the trucks is between 14,400 and 14,500 pounds, Coover says.

"The Model 365 is typically spec'd as a concrete mixer in super-heavy-duty configuration," he notes. "I was real surprised that they were game to spec one as a small-sleepered road truck. These trucks came in 1,200 pounds lighter than their regular set-forward-axle conventional."

He gave up nothing in terms of strength and durability, and the cost was very competitive. He got the trucks on a Paccar full-service lease for less than he'd pay an owner-operator - and PacLease takes responsibility for maintenance and warranty issues as well as residual values. One wouldn't expect PacLease to spec and put into service a truck they didn't expect to make money on.

Working with the leasing experts at The Larson Group, the Peterbilt-PacLease franchise in Springfield, Kan., Coover selected the lighter weight components he needed while the engineering team did the engineering calculations.

"I can't imagine how many times PacLease must have run and rerun these numbers. A few of the sales guys told me they couldn't build a truck this light, but they did," says Coover. "Since Paccar is on the hook over the life of the lease for the stability of the trucks, they must be thinking it's still robust enough for them to recoup the risk and make a profit. That was good enough for me."

There are a bunch of obvious alternatives right off the top when spec'ing light. If you don't need big-block torque and horsepower, go to a medium-range engine, an 11- or 12-liter engine instead of a 14- or 15-liter model. A 9- or 10-speed transmission will weigh less than a 13- or 18-speed, and the lower engine torque will allow for a lighter-spec driveline, and lightweight brake drums can save 120 pounds on a three-axle tractor. Under-hood air cleaners are lighter - and more aerodynamic - than dual cowl-mounted breathers, and aluminum can make a difference in many instances.

Switching to aluminum components is a good strategy, if cost and weight savings are calculated carefully, says Kenworth's on-highway marketing planning manager, Andy Zehnder.

"The cost benefit analysis of an aluminum frame, for example, just doesn't pay out anymore," he says. "But it works for crossmembers. We use a five-piece crossmember with aluminum gussets to minimize weight while maintaining strength. They will save you close to 10 pounds each and the cost/benefit holds."

An aluminum frame might be 100 pounds lighter over 240 inches, but the cost increase over steel would be nearly prohibitive today. Other popular aluminum alternatives that still work include wheels (268 pounds) and air tanks (40 pounds).

Cost/Benefit Analysis

One of the easiest cost-per-pound weight savings to justify comes from wide-base single tires. According to Michelin, fleets can save 740 pounds when spec'ing its X One tires on aluminum wheels over a comparable dual-tire spec. And the wide-base singles have been proven to reduce rolling resistance, thereby providing quantifiable fuel savings. No brainer, right? Not always.

Interestingly, Coover Trucking decided against using wide-base single tires despite the significant weight and fuel savings. In his world, on-time deliveries are everything.

"We looked at them very seriously, but in the end, our biggest concern was the delivery schedules. We're on a schedules with a 15-minute window. The loads are all timed, so we can't afford to be late and risk shutting down a job," Coover told us. "One blow-out and we've messed that guy's day right up. On dual tires, a driver could most likely limp in to make the delivery, but with the wide-base singles, when one goes down, the truck goes down."

Coover avoids retreaded tires for the same reason. "All the tire problems we've ever had were related to treads peeling," he says. "Sure, we could work harder at managing tire pressure, but there's a cost to that, too."

Keith Herrington, Freightliner's product marketing manager for the on-highway market, told us spec'ing for lighter weight used to be a big topic back in 2000/2001, but it's drifted off the radar screen in recent years. Linehaul trucks don't run at max GVW that often, so those truck owners really haven't embraced lightweight specs in a big way, he says, adding it's a different world for the bulk and the beverage haulers.

"In that world, every pound they can take off is another pound of product that can load. In the linehaul truckload world, the concern is more life-cycle cost and durability," Herrington says. "EPA is pushing their SmartWay concept. Their brochures say if you can take 2,000 pounds off a Class 8 truck you can save a certain amount of fuel. While it sounds good in theory, with the amount of influence weight has, you can accomplish the same thing in other ways. Drivers remain the number one influence on fuel economy; next is the most direct or efficient route to destination."

Herrington is quick to point out the irony of one branch of EPA urging truckers to spec light for fuel savings, while another is forcing close to 1,000 pounds of extra hardware onto trucks to meet emissions reductions targets (see "Trucking's 800-Pound Gorilla," page 86).

"EPA has added so much weight to a vehicle that we need some kind of relief," he says. "We need to have an allowance for the weight EPA has added to the truck."

That doesn't mean there isn't room for rationalization in equipment utilization. In fleets where it's feasible, Herrington suggests spec'ing regionally.

"Maybe it's time we began to regionalize the operation such that it makes no sense to run a truck spec'd for mountains in a place where it's flat, and the horsepower isn't needed. How many nights does the driver spend in the truck? Does he need a 72-inch sleeper or can he use a 60-inch bunk? Take off a fuel tank for local trucks. Optimize for a given area," he offers. "There are ways to save money through improved fuel economy and lower weight without adding upfront cost to the spec. "

Of course, there's an entirely different cost/benefit calculation in the vocational market. Weight has always been a concern, balanced about equally with durability. Fuel traditionally hasn't been a huge concern. According to Sean Coleman, director of sales and marketing for truck products at Hendrickson, that all changed when fuel hit three bucks a gallon.

"Everyone started asking for ways to cut fuel bills," he says. "People are thinking twice about overloading because of the increased fuel consumption. The value of weight savings in a vocational truck has all of a sudden increased."

Coleman notes that the raw materials costs of heavy steel suspensions have gone up dramatically in recent months, and aren't expected to drop anytime soon. While many of today's newer lightweight suspensions have lower material costs, they also offer reduced weight and additional features and benefits such as better ride, improved roll stability, and less maintenance.

"Compared to another OE steel suspension, our HaulMaax heavy vocational suspension can save the operator 690 pounds. That a lot of weight just in a suspension," Coleman says.

But that's not the end of it. Like the highway haulers and the lean and mean bulk and beverage crowd, vocational trucks stand to gain from improved fuel economy on the empty return trip. Even if only marginal, it's still an improvement, and it comes a cost not as hard to justify as one may have thought previously.

What's the difference? Inflationary pressures on raw material, Coleman says. "Steel costs have skyrocketed. Heavy steel spring suspensions are becoming much more expensive. If you have an option that saves 500 pounds, on a relative basis, the cost difference has narrowed," he says. "The gap in cost between the newer light-weight components and the legacy steel suspensions has narrowed, making the newer options more attractive."

And Trailers Too

With much of the upcoming OE focus on weight reduction being applied to the power units, the trailer people continue to improve suspension technology with an eye toward weight reduction for fuel economy gains.

Jim Crowcroft, director of marketing at Hendrickson Trailer Suspension Systems, says there can be a difference of 25 percent between the lightest and the heaviest trailer suspension in the on-highway market - "that's at least half a pallet [of] payload," he says.

At 200-300 pounds per axle, the savings are hard to ignore - that can make the difference between a pass and a ticket at a scale.

Crowcroft says while there are still a few purchasers who are very specific about what they want, right down to spec'ing seals and bearings, the trend today is toward a systems-based approach. That has a lot to do with warranty and customer support, but it has enabled manufacturers to design in improvements versus adding-on. "There's a lot more opportunity to optimize if you're building the whole system," he says. "When you're looking at a 10-year, million-mile service life, you can't afford to skimp on the design or materials."

A lot can be done with materials these days, and there's a lot the purchaser can do to shave weight, but it all comes down to dollars. The more you're willing to spend, the lighter you can make a product. Composite materials, for example, offer a respectable trade between weight and cost, but since that stuff is petroleum-based, it's getting more expensive right along with aluminum and steel.

Wide-base single tires have a weight-savings role on trailers too. Michelin claims a savings of about 40-50 pounds per wheel end using X One XTA or XTE tires compared to a comparable dual assembly. Taken as a whole, cutting pounds will save fuel (see "The Value of Weight," below), but from a spec'ing consideration, Hendrickson's Crowcroft says the wide-base singles haven't really caught on in the second-user market.

"The secondary market generally isn't as fond of wide-base singles, typically," he cautions. "You can't always convert back to duals easily with an axle spindle designed for wide-base singles. Our P90 spindle used in the Quaantum suspension has no issues with conversion."

That could change in time, as the big wide tires gain acceptance, but it's a point worth considering when spec'ing your next trailer.

And speaking of resale, Kelly's Blue Book suggests there's good cost recovery to a lightweight spec. Aluminum wheels will generally fetch back about $2,500. A Hendrickson Airtek suspension could return a $400 premium at trade time.

Coming Trends

You can't put 10 pounds of potatoes in a 5-pound bag, yet that's the challenge OEs face now, and more so going into 2010.

"OEs have 500- to 800-pound weight reduction targets just to stay even, with EPA 2010," notes ConMet Vice President Mark Wagner. "It's not just EPA, but most of the pressure is emission-related. APUs weigh 400 pounds. Hang one of those on the chassis, you have to take the weight out from somewhere to stay legal."

And there's pressure to keep steer axle limits at 12,000 pounds.

"You'd like to keep the 12K axle if you can, because a 13.2 axle adds weight and cost," Wagner says. As you can see, there are a lot of factors driving the use of lightweight parts."

There's not much a fleet owner can do when it comes to spec'ing 500 pounds out of the chassis. That may be the OE's task, but guess who will pay for it?

At first thought, weight-reducing specs don't seem to make that much sense given the increase in material prices - especially aluminum. Lighter alloy materials have risen higher than traditional options like cast iron and steel. Metal prices may have doubled, but fuel has gone up by a factor of five.

Dave Coover says he expects his lightweight spec to earn him a nickel a mile in extra revenue. Today, that might not be profit, but savings on fuel costs. In linehaul applications where weight savings are harder to justify, there are still quantifiable savings to be had in fuel consumption.

As illustrated in the "Value of Weight" box, opposite page, a typical truckload carrier could realize a return of $2.60 for every pound of weight saved on the vehicle. For bulk haulers, the return could be as high as $3.80.

Heavier steer axles are already driving a change in steer tire spec. Michelin's Don Baldwin says he is seeing a move to Load Range H from Load Range G due to this need.

"This is not a problem for Michelin, because we already have an XZA3 LRH steer tire that can carry 14,320 pounds at 120 psi," he says, adding, "we already have technology that would allow us to go to even heavier loads if the need arises."

And there's an ironic twist to all this concern about weight: drivers are getting bigger and bigger all the time, and they're looking for bigger cabs to accommodate their increasing girth. Load a pair of 250-pound team drivers into a cab with all their gear, and you've wiped out any savings from all the lightweight components money can buy. Perhaps a less expensive alternative over time would be to put a gym at the terminal and pay drivers to use it.


Ironically, that's close to what truck makers will be dealing with come 2010. With all the EPA emissions iterations since 2004 culminating in the near-zero-emissions heavy truck engine in 2010, about 800 to 1,000 pounds of gear, piping, cooling capacity, fluid tanks, coolers, brackets, clamps, and aftertreatment devices will have been added to a typical truck chassis.

For the most part, chassis weight is a OE issue, not a customer spec problem, but there are certain configurations on the road today running 11,800 pounds or more on the steer axle - before hooking to the trailer. The obvious solution is a 12,600- or a 13,200-pound steer axle, but some of the EPA-induced weight can wind up on the drive axles, too. In these cases, drivers are limited in how they set the fifth-wheel slider. Once upon a time, steer axles took up 400-800 pounds of payload. We no longer have that kind of latitude up front.

"That's something we're talking about every day," says Kenworth's Andy Zehnder. "What we're trying to do is weigh what we can do with fuel capacity or frame layout to minimize the impact on the front axle so we can continue to offer the 12,000-pound front axle in all applications."

Zehnder says it won't be such an issue in local or regional applications where 50- and 100-gallon fuel tanks are the norm, but it will affect highway trucks with their higher fuel capacity. "With 250 gallons on board, you can be overweight before you start if you don't have a 13,200-pound axle."

Need a few more gray hairs? Add a 400-pound APU to the chassis to meet state and local anti-idling laws. Now you're looking at close to 1,200 pounds or more of mandated weight that drives nothing to the bottom line.

Freightliner's Keith Herrington says it's time the feds came to the table with a weight allowance for the EPA-mandated paraphernalia.

Referring to the "APU weight credit" granted in 2006, Herrington is calling for relief in the gross weight as well as the tractor axles.

"We should be pushing for a 2,000-pound spread across the tractor axles, and an increase in the GVW to 82,000 pounds for all 2010 and newer trucks," he says. "The trailer tandems wouldn't need to change because the extra tractor weight won't affect them."

Steer axle weight has become a serious issue at the OE level, but not yet on the street because there aren't many '07 trucks on the market yet. As they gain traction, weight will become more of a concern, and certainly by the time EPA 2010 becomes reality, fleets will have taken notice.

The EPA-related weight gains are significant in their own right, but advancements in motive power technology are severely hampered by current weight limits. Herrington points to emerging hybrid technologies that could benefit Class 8 trucks, including a variation on the diesel-electric drive theme, as found in locomotives. There's certain efficiencies in such a system that truck makers would never be able to take advantage of because of the weight, he points out.

"If we had a variance on the 80,000-pound envelope, maybe the technology could proceed. Now, things are requiring that to change. What I don't see is people pushing the change," he laments. "I'm surprised ATA hasn't been more aggressive in asking - at least - for an EPA-weight allowance on the steer axles. That wouldn't be for payload, just for the weight increases that have been federally mandated."


With the best of intentions, the Energy Policy Act of 2005 made allowances for the extra weight associated with auxiliary or alternate power units (APUs), but the application of that provision remains somewhat of a mystery. The Federal Highway Administration interpretation is that states were not required to follow the federal lead. The resulting patchwork of states that allow the weight tolerance and those that do not has left truckers scratching their heads. Even among those that do, local enforcement officials may or may not be aware of the exemption.

The list of states officially granting the exemption is a short one. To the best of our knowledge, it includes Arkansas, Kansas, Maine, Missouri, New Mexico, Nebraska, Oregon, Washington and Wisconsin. Other jurisdictions may allow the extra weight anyway, some include in it pre-established tolerances, and some will whack you for running 20 pounds over.

FHWA says the exemption should apply to axle, tandem, gross, or bridge weight on the tractor only. It should allow up to 400 pounds or the weight of the APU unit, whichever is less. The APU must also be accompanied by written manufacturers' weight certification, or a list of component parts if the unit was "homemade." And, the unit must be in "working order" - which raises questions about temporarily broken down units, since one would have to question the wisdom of mounting a broken APU on the truck, just to gain the exemption. Only in America ....


With the cost of fuel rising over the last year, it is more important than ever to consider the value of weight savings. Though there are several factors to consider when determining the value of weight savings on your tractor-trailer, these simple formulas will help you determine the potential value of weight savings when spec'ing a truck.

Value of Weight Savings Formula - Fuel (VOW Fuel)

VOW Fuel ($/lb) = (Fuel Price/Gal) x (Miles/Yr) x (TMC Fuel Improvement Factor/lb) x (Payback Period) / (mpg)^2

Where TMC Fuel Improvement Factor = (0.375 mpg / 10,000 lbs)

Referenced from TMC RP1112 Chart B in the 60,000 to 80,000 GVW range

VOW Fuel ($/lb) = ($4.70/gal) x (120,000 mi/yr) x (0.375/10,000 mpg/lbs) x (2.5 yrs) / (6.5 mpg)^2 = $1.25/lb

Value of Weight Savings Formula - Profit (VOW Fuel)

VOW Profit ($/lb) = (Miles/Yr) x (Revenue/Mile) x (Profit Margin) x (Payback Period) / (Weight of Cargo)

VOW Profit (Dry Freight) = (120,000 mi/yr) x ($1.95/mi) x (20%) x (2.5 yrs) / (45,000 lb) = $2.60/lb

VOW Profit (Bulk Tanker) = (120,000 mi/yr) x ($2.85/mi) x (20%) x (2.5 yrs) / (45,000 lb) = $3.80/lb

Putting It All Together Formula - VOW

Depending upon your typical running situation, you can determine one value of weight savings for your commercial vehicle by estimating the percent of time you have a fully weighted out truck vs. less than full truck load weight.

Value of Weight ($/lb) = (% Time Full Load) x (VOW Profit) + (% Time Less Full Load) x (VOW Fuel)

VOW = (75%) x ($3.80/lb) + (25%) x ($1.25) = $3.16/lb

Weight savings can be achieved in various ways as shown in appendix C of TMC RP1112.

- Calculator courtesy of ConMet

About the author
Jim Park

Jim Park

Equipment Editor

A truck driver and owner-operator for 20 years before becoming a trucking journalist, Jim Park maintains his commercial driver’s license and brings a real-world perspective to Test Drives, as well as to features about equipment spec’ing and trends, maintenance and drivers. His On the Spot videos bring a new dimension to his trucking reporting. And he's the primary host of the HDT Talks Trucking videocast/podcast.

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