Weigh to go

Avoiding the costs related to making trips to commercial scales allows onboard scales to pay for themselves in a relatively short period.

Few aftermarket items have more potential to cut costs than onboard scales. They can reduce or eliminate trips to a platform scale, saving miles, time and fees.

The cost for these various devices begins at just under $100 and can exceed $2,000. Even at the higher prices, though, the investment can pay for itself fairly quickly when you consider the fees at commercial scales, the cost of out-of-route miles to reach them, and the fine when you’re hit with an overweight citation.

Of the three general types of onboard truck and trailer scales, the most economical are pneumatically driven analog scales. Right Weigh’s products, for example, range from $95 for the standard 2.5-in. exterior-mounted gauge to $265 for the newly introduced 4-in. silicone-filled gauge and stainless steel enclosure. Installation time is said to be less than an hour.

This pricing, far below that of competitors’ products, actually has worked against sales because buyers “automatically question the quality,” says Scott McCulloch, communications director for Right Weigh Load Scales in Sherwood, Ore. “We countered this problem by letting truckers try our scales before committing to buy them. We also offer a complete money-back guarantee on everything. We’ve discovered that once people use our products, they keep them.”

Right Weigh’s strategy also seems to be working with some bigger fleets. Its units are on most of the vehicles owned by Sunbelt Rentals of Charlotte, N.C. And the company recently announced a preferred vendor deal with Prime Inc. of Springfield, Mo.

The other two scale categories are pneumatic digital and load cell (technically “transduction”). Pneumatic digital and pneumatic analog are most commonly used on air-suspended vehicles. Load cell scales are designed for steel-spring or walking-beam suspensions and other sorts of non-air systems.

Load cells have been around the longest, and they’re based on a device invented more than a century ago: the strain gauge. The principles it uses are fairly simple, at least in theory. Electrical resistance changes as its current path, a piece of metal in this case, is deformed or bent under load. More weight causes more bending, which causes more resistance. This information is converted to another measurement, such as pounds or kilograms. The real trick, of course, is to develop a system that accurately matches tiny electrical swings to specific weights.

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Load cell scales are the preferred choice of log haulers, mine operators and refuse collectors. The technology is renowned for its accuracy and durability in nearly any operating environment. Its main downsides are cost and complexity. Pricing starts at more than $2,000 for a tractor or straight truck and increases steadily from there. Also, these systems must be professionally installed, which can take days.

One of the biggest companies in this arena is Stress-Tek of Kent, Wash., which makes Vulcan onboard scales. Stress-Tek started in the late ’70s, focusing on the needs of timber haulers in the Northwest. Today, it offers a wide array of products and services catering to all types of trucking, as well as military, aerospace and oil exploration applications.

Those who choose load cell scales do so for two main reasons: a need for precise weighing and a lack of viable alternatives, says Eric Elefson, Stress-Tek director of sales and marketing.

“Our customers have come to expect the greatest accuracy money can buy,” he says. “Also, many of them run a lot of miles off road, across terrain unsuitable for air suspensions. Load cells are the only weighing technology they can use.”

Although impressive, the capabilities of load-cell scales probably exceed the needs and budgets of typical over-the-road truckers, most of whom operate air-suspended trucks and, increasingly, trailers. The largest companies supplying this market segment are Air-Weigh of Eugene, Ore., and TruckWeight of Halifax, Nova Scotia. These two specialize in pneumatic digital scales. The most obvious difference between their wares is in the method of delivering weight information: Air-Weigh uses a wire or a truck’s communication network; TruckWeight uses radio frequency.

Air-Weigh scales range from $650 for a trailer model to about $2,000 for a system that weighs all five axles of a standard tractor-trailer. Total-vehicle weighing became possible in 2006, when the company unveiled a sensor that measures steering axle deflection. The company’s latest system is called LoadMaxx. It’s designed to work in tandem with vehicular onboard computers and data logging devices. Among other things, LoadMaxx features updated software, programmable weight alarms and an interface for an optional inclinometer that indicates whether the surface beneath the truck is level enough for an accurate weighing. Air-Weigh scales can be installed in less than an hour, according to the company.

Truckers long have relied on air-suspension pressure gauges to give them some rough idea of loaded weight, but this approach is fraught with problems, says Michele Lukowski, Air-Weigh marketing manager. First, psi-to-pounds conversion is loose at best. Second, air suspensions vary in loaded pressure, leaving those in slip-seat and drop-and-hook operations wondering whether 35 psi has the same weight value across the spectrum of tractors and trailers.

“Truck manufacturers will one day make onboard scales standard equipment,” Lukowski says. “More and more advanced technology is being integrated into trucks all the time, and buyers’ expectations of information systems continue to rise as well.”

Peter Panagapko, president of TruckWeight, agrees. “It’s just a matter of time,” he says, “and demand from buyers.” Today’s truckers understand the benefits of onboard weighing, Panagapko says, and they realize the return on investment from such equipment is fairly short: six months to a year, according to his calculations. Still, he estimates that fewer than 10 percent of over-the-road truckers have purchased the devices. “That’s actually good news for us,” he says. “It’s a growth market.”

Founded in 2002, TruckWeight quickly has established itself with its Smart Scale, a unit composed of two main parts: an air-suspension sensor and a hand-held wireless digital receiver. Installation time is said to be less than a half hour. Panagapko says the Smart Scale ($1,040 for tractor alone, $1,590 for tractor-trailer) is unaffected by road chemicals and other potential corrosive substances because it has no wires, and the battery-powered sensor is weather-sealed.

The method for measuring air pressure and converting it to a weight value hasn’t changed much over the years, but temperature always had been a problem because it affected readings, Panagapko says. “We were able to develop a patented process that enabled our system to maintain a high level of accuracy throughout a wide range of temperatures.”

The Smart Scale soon will be even smarter. TruckWeight is introducing a receiver module that will connect to a truck’s onboard communications system. In addition to sending weight and trailer I.D., the module will transmit tire pressures, temperature and humidity levels of cargo, security data and more.

The company also is unveiling a sensor for non-air-suspended steering axles. “We’ve acquired the rights to some strain-gauge (load cell) technology, and we’re incorporating it with our current wireless system,” Panagapko says. “This will provide a full-vehicle weighing for truckers who want that.”

Onboard scale: Payback time
The return on investment with onboard scales varies widely, according to your type of operation, typical loads and usual routes, as well as how much you invest in an onboard scale system, which also can vary widely.

A small portion of truckers rarely need to axle out, but others must do so with almost every load. Below are some of the cost savings that can be realized in a fairly average long-haul trucking operation.

Scale fees:
Two $8 scales per week X 50 weeks = $800 / year

Foregone income due to out-of-route driving:
500 out-of-route miles X 50 cents per mile net income = $250 / year

Cost of fuel due to out-of-route driving:
500 out-of-route miles X 50 cents per mile fuel cost = $250 / year

Cost of one overweight ticket / year = $500

Total: $1,800 / year

The immeasurable value in onboard scales is the peace of mind from knowing your axle weight while still at the loading site, and being able to correct load weight right there.