Recently, independent organizations have conducted studies on the effect that tonneau covers have on the aerodynamic drag of pickup trucks.
From Auto Trim & Restyling News - August 2001 From "Tailgate Talk - Does Removing A Tailgate Affect Fuel Economy?" By Bruce W. Smith
According to many experts, the best way to improve a pickup's fuel economy is to leave the tailgate up and cover the bed with a quality aftermarket tonneau cover. "Tonneau covers on pickup boxes reduce aerodynamic drag," said Ford's Jack Williams. "We've seen reductions of about 8 to 10 percent on the F150.”
From SEMA Specialty Equipment Marketers Association - January 2007 At AeroDyne Wind Tunnel LLC, a site often used by the NASCAR community “How Tonneau Covers Affect the Coefficient of Drag” By Megan McKernan Research & Information Specialist
The new tests confirm that hard tonneaus reduce the coefficient of drag of a moving pickup truck by an average of 6.5% or higher. These results, combined with recent pickup truck road testing, prove conclusively that adding a hard tonneau improves fuel economy by 6% - 9%, depending upon driving conditions.
