Trucks at Work

Aerodynamics and trailers

Trailer aerodynamic devices have gone from being fringe products to accepted, mainstream components all due to the dramatic fluctuations in fuel prices we’ve experienced lately.” –Andrew Smith, CEO, ATDynamics

Spent some time with ATDynamics here at the Mid America Trucking Show talking about the almost 180 degree shift in thinking that’s occurred over the last few months in the trucking industry about the aerodynamic footprint of freight trailers.


Andrew Smith’s quote above really says it all I think – no longer are trailer “boat tails,” side skirts, even wheel covers considered “fringe” components anymore, right up there with cow magnets and other snake oil goodies.

After the volatile price swings in oil and diesel prices over the last year, fleets understand that improving fuel efficiency – no matter how small the increments – helps save them a ton of money.

“The one thing we know about fuel prices know is, while we don’t know whether they will go up or down, they will definitely change – and change dramatically,” Smith told me here at the show during a press conference his company put on to unveil some new trailer aerodynamic devices.

[Smith and Jeff Grossmann, director of customer fulfillment for ATDynamics, talk about the company’s new trailer side skirts and this new awareness regarding the importance of fuel savings in the clip below.]

“What fleets need to do now is get to the point where they are not so negatively impacted when fuel prices are high, yet also benefit when fuel prices are low,” Smith explained to me. “The point is the U.S. trucking industry and U.S. consumers as a whole cannot continue to transfer huge amounts of wealth to the oil suppliers of the Middle East. That can only come from better approaches to minimizing fuel consumption.”

In 2008 at Mid America, the company introduced its patented rear-mounted “TrailerTail” – foldable panels that fit over the rear doors of a trailer to reduce drag – can improve fuel efficiency by 5.1% at 62 mph based on SAE J1321 testing.

Now ATDynamics is bringing a new “side skirt” design to the trailer market, built with a durable yet flexible thermoplastic composite material so it “bends” rather than dents or breaks. These new side skirts – manufactured in a partnership with Montreal-based Transtex Composite Inc. – demonstrated a 7.4% fuel-efficiency improvement at 62 mph, based on SAE J1321 testing validated by the U.S. Environmental Protection Agency’s SmartWay program, said Smith.

Jeff Grossmann, director of customer fulfillment for ATDynamics, noted that these new side skirts are designed to withstand extreme temperatures and uneven terrain and should last 10 years. The company is confident enough in the design and the material to offer a five year warranty on them.

“Performance means nothing without durability,” said Grossmann. “We looked at the landscape of side skirts that are on or almost on the market. Over the long term, the panels used in the Transtex design should provide the lowest cost operation to fleets.”

ATDynamics even offers special “wheel covers” that help improve fuel economy, though only by a measly 0.2% when covering the back wheels of a tractor and 0.5% on the trailer’s wheels. Yet when diesel surged over $5 per gallon in many parts of the country last summer, such incremental improvements would’ve saved a lot of money.

The company also brought another interesting new product to the market – the “SuperSpare” tire mount, designed so fleets that use wide-base tires can mount a spare unit on either the trailer or tractor while not affecting the under-chassis airflow, which would increase drag and thus impact fuel economy.


Developed in partnership with Mesilla Valley Transportation of Las Cruces, New Mexico, the SuperSpare is compatible with any tractor with 43 inches of clear frame rail between its fuel tank and drive wheels. On trailers, it fits between cross members on the underside of a trailer and allows unobstructed access to a spare tire on a trailer equipped with side skirts, said Grossman.

But none of this stuff comes cheap – and that fact needs to factored into a fleet’s fuel savings calculation. Retail pricing for the company’s TrailerTail, for starters, starts at $2,800 per unit. One set of the new side skirts (which weigh 175 pounds combined and requires two people three hours to install) runs around $2,200 for a 53-foot trailer. The SuperSpare costs $385 per unit, whether used on a tractor or trailer, and a set of four “wind shield” wheel covers will set you back $295.

Still, it’s wise to look at the “big picture,” said Smith. If a fleet installed all of the company’s aerodynamic products on a big rig – wheel covers, side skirts, and boat tail – the total fuel economy improvement for the vehicle would improve 12% when running down the road at 62 miles per hour. “The savings really come down to how many miles a tractor-trailer drives every year at highway speed,” he explained to me. “The more miles you log, the more you save.”

For fleets in California, however, none of this is academic, he stressed, as new regulations promulgated by the “Golden State” are going to mandate trailer aerodynamic improvements in the very near future.

Under first-of-their-kind standards for trailer aerodynamics approved by the California Air Resources Board (CARB), effective in phases beginning in 2010, most 53-foot dry vans operating in the state must be equipped with aerodynamic devices that improve fuel efficiency by at least 5%, while for refrigerated trailers the benchmark is 4%.

That’s yet another example of why trailer aerodynamic devices are getting a lot more attention these days.