For truckers large and small, trailers are no longer an afterthought to their business models. Fleets of all sizes want more capability, longevity and options where trailers are concerned. They want equipment that will contribute to fuel savings and productivity. Even small changes, such as wider interiors, can make a big difference to a carrier's bottom line.
“Let's compare our traditional sheet-and-post dry van trailer, the HT Hy-Cube, to our new HT Composite model,” says Stuart James, vp-sales for Hyundai Translead. “That composite trailer can offer a fleet three-quarters of an inch more in width, maybe a little less. But that extra width can make all the difference in the world to a TL or LTL carrier in the general freight market, where many ‘cube out’ on loads before they reach maximum weight-carrying capacity.”
The HT Composite, which offers a full 101.5-in. panel-to-panel interior width, is built to allow for quick individual side-panel replacement without removing the stiffeners, meaning less downtime.
The two trailer designs may be relatively equal in price, but their differences are significant. For example, the material used to make a composite trailer's sidewalls is considered hazardous and must be disposed of accordingly, James points out. Also, the majority of truck stops that offer trailer repair services still stock more sheet-and-post materials than composites.
Another trailer characteristic fleets are especially interested in is a longer life cycle. “We're being told by our customers that they've been compelled to reduce the life expectancy of their trailers due to corrosion from liquid calcium chloride and other snow-removal chemicals,” says James. “That's why you are seeing so many corrosion reduction solutions coming to the market now.”
The reason corrosion is a bigger concern among trailer manufacturers revolves around the replacement of traditional rock salt with liquid calcium chloride and its close cousin, magnesium chloride. While these chemicals aren't necessarily any more corrosive than rock salt, they cling to metal much more aggressively, creating a longer time frame for their corrosive properties to act, says Rod Ehrlich, chief technology officer for Wabash National Trailers.
“We've also seen an increase in the amount of ‘road salting’ activity that goes on in the winter now,” Ehrlich notes. “We pre-treat the roads if there's even a potential chance of snow. That means that instead of 10 applications per season, we're seeing these chemicals applied upwards of 30 times a season. That creates a lot more exposure to these corrosives.”
To block these chemicals from getting a toehold, Wabash is experimenting with thermoplastic coatings on the rear frames of its Duraplate-brand trailers. “The end result is seven times better capability in reducing the ‘creep’ of corrosion,” Ehrlich explains. Wabash uses the same thermoplastic in the foam resin mix used as core material for its trailer doors.
James notes that Hyundai now offers a hot-dipped galvanized steel rear frame, rear-impact guard, landing gear mounting brackets and bracing, license mounting plate and midturn-signal bracket for more corrosion resistance.
Last year Great Dane rolled out CorroGuard, a corrosion-resistant undercoating compound for steel components of van underbodies and a two-step epoxy primer-urethane combination for dry freight van rear frames and platform trailers, says Chris Stolfe, senior manufacturing engineer. The spray-in-place thermoplastic elastomer coating, which is applied to suspensions and support gear, is designed to be resistant to de-icing chemicals, road debris, climate fluctuations, ice and snow; it's airtight and watertight, and will not crack, warp, flake or split, according to Stolfe.
Manufacturers are also looking for ways to make trailers more robust, so they can better weather the wear and tear they will inevitably be subjected to. For example, Utility Trailer Manufacturing designed a new prep package for its 3000R model trailers equipped with hybrid refrigeration units. Craig Bennett, senior vp-sales & marketing, says it offers an improved interface between the trailer and the refrigeration system.
“We recognized that the interface between the trailer and refrigeration system has an impact on overall performance and reliability, especially in demanding applications like multi-temperature, where heavy forklift traffic, multiple door openings and movable bulkheads make them more prone to damage and wear,” he notes.
Bennett says that a number of new features have been incorporated specifically for hybrid multi-temperature applications. These include a flush, heavy-duty, divided aluminum trough that houses refrigeration lines and electrical cables in separate compartments; a full-length, grounded, copper channel surrounding the high voltage cable; and a 1/4-in.-thick trough cover to better protect the high voltage cable from damage from forklift masts and shoring bars.
To improve life expectancy for trailer interiors, Great Dane introduced a single-sided laminate interior steel lining to replace plywood and plastic linings, thus protecting against forklift damage while also increasing cubic capacity comparable to standard plate and composite wall trailers.
“Fleets today recognize that there are multiple areas they need to look at when it comes to improving overall lifecycle value, not just one or two,” stresses Brandie Fuller, Great Dane's vp-marketing. “They are all looking at what affects the cost of the box.”
Building upon the improvements they've already achieved, trailer makers are looking at ways to develop products that last longer, thus becoming more cost-effective assets for fleets. For example, Mark Roush, director of engineering for Vanguard National Trailer, recently built two prototype 28-ft. pup trailers and a 53-ft. dry van unit that use adhesives to hold the sidewalls of a dry van unit together, with rivets needed only along the top and bottom.
“Glue doesn't rust and it holds just as well on brackets as rivets do, even better in some cases,” he says. “The glue we're talking about has a sheer strength of 2,000 psi, whereas the average rivet has a maximum sheer strength of 1,200 psi.”
One of the most costly parts of manufacturing a trailer is the time it takes to rivet the sidewall to the frame. In addition, every rivet represents a metal-on-metal contact point where rust and corrosion can develop over time, Roush says. “With glue, you're using one single sheet of aluminum sidewall without rivets,” he notes. “You're taking a tremendous amount of hours out of the production process, yet giving the trailer more durability in terms of corrosion prevention.”
Roush is working on a trailer floor made with a pultruded composite material, i.e., lightweight yet durable resins pulled into specific shapes with specialized machines before they harden. This enables him to slice 700 lbs. out of a standard 53-ft. dry van using a composite floor, while also improving traction and longevity.
“The perennial problem with wooden floors is that over time, they get wet and start to rot,” he explains. “While oak is the best in terms of resistance to rot, it's also one of the most expensive woods on the market.”
Roush is also starting to envision using pultruded-style materials to make an entire trailer, with sidewalls, floors and doors built separately and then combined using mainly adhesives, with bolts and rivets at major connection points. That would really save on trailer unit weight, he believes.
It all comes down to finding ways to improve a trailer's lifecycle cost “footprint,” says Hyundai's James. “Total cost of ownership is becoming the key now: How can I maximize my trailer's productivity and useful life, while minimizing downtime and maintenance cost?” he says. “That's why you are seeing far more technology packed on trailers today — tracking devices, automatic tire inflation systems, etc. It's all about asset management, which is creating a sea change in terms of how fleets view their trailers. They're no longer just boxes on wheels.”
Special case: vocational trailers
Two of the most important issues for trailers used in vocational applications are customization and heavy loads, explains Mark Holtz, vp-sales & marketing for East Manufacturing. So design changes for dump trailers, refuse transfer units and flatbeds are often very different than for their dry van and refrigerated counterparts.
“Virtually all vocational trailers must be regional-specific, as roadway and bridge weight laws vary widely from state to state,” he says.
“Durability and reliability are also much more critical as these trailers run much more heavily loaded on a daily basis than dry van or refrigerated units. That's why price is often the third or fourth priority,” notes Holtz. “It's not that price isn't important to vocational fleets; it's that proper specs are more critical. The trailer must [be able to] do what the fleet needs it to.”
Nonetheless, manufacturers are finding ways to make vocational trailers more cost-effective. East recently introduced a “smoothside” dump trailer to help improve fuel economy, for example. Reducing weight is also important, as less trailer weight means more payload capacity and thus revenue for bulk haulers, according to Holtz.
But just like their dry van and refrigerated counterparts, corrosion is also a problem for trailers in the vocational sector. Holtz notes that East is taking steps to “isolate” the aluminum material in its dump trailers from the iron- and steel-based components in the axles and fifth wheels since the connection points between different types of metal can aggravate corrosion issues.
“We're using thin stainless steel buffers between dissimilar metals to cut down on corrosion,” he says. “We're also making sure the wiring and trailer lights are fully sealed and that we use non-conductive grease in all the fittings. Fleets expect these trailers to last eight to ten or more years, so we're making sure all the design elements are in place to prevent corrosion from cutting that life expectancy short.”