At the Mid-America Trucking Show, ATDynamics told the results of testing various fuel efficiency devices.
Transtex side skirts sold by ATDynamics demonstrated a 7.4% fuel efficiency improvement at 62 mph, based on SAE J1321testing validated by the EPA SmartWay program.
ATDynamics' patented rear-mounted TrailerTail improved fuel efficiency by 5.1% at 62 mph in the SAE testing.
Michelin X-one tires showed a 9.7% fuel efficiency gain.
The side skirts, the Freight Wing Belly Fairing by Transtex Composite Inc and sold by ATDynamics, were re-tested to find the best of three configurations — a long panel mounted straight, or mounted at a slight angle, or a short panel at an extreme obtuse angle in front of the trailer tandem.
The best performance was by the long panel mounted at a slight five degree angle to the longitudinal axis of the trailer. Actual dimensions were a 22.5-ft. long panel, 35.5 inches wide and mounted 7 inches above the road surface. The forward end of the panel was tucked in behind the landing gear supports, 20 inches from the edge of the van.
This angled mounting achieved a 7.45% fuel efficiency gain. The same type panel mounted straight or parallel with the long axis of the trailer showed only a 3.90% fuel efficiency gain. The poorest improvement was by the short panel mounted at an obtuse angle ahead of the tandem axles, showing only a 1.85% fuel efficiency improvement.
Mounting the side skirts low with only seven inches road clearance could mean lots of road damage to the skirts. However, ATDynamics claims the flexible thermoplastic materiel is extremely resilient and will spring back into shape following an impact. The long panels are hung from the trailer floor crossmembers using continuous steel hinges and thermoplastic bracing. A set of skirts weighs 175 pounds and requires two workers three hours to install.
Because of the importance of wide-base single tires in achieving fuel efficiency gains, ATDynamics announced at the Mid-America Show a new product, the SuperSpare tire mount. It allows a wide-base tire to be carried on either the tractor or the trailer, even with side skirts.
Advanced Transit Dynamics is based in South San Francisco CA and says it is working with 60 clients and has installed 600 sets of side skirts. Twelve fleets are testing the TrailerTail, which was introduced a year ago at the Mid-America Trucking Show.