Keep it up

We've all seen owners of pickup trucks driving with their tailgates down. Lowering the flap at the back of the truck must improve aerodynamics and save fuel... right?  Wrong!

In fact, driving with your pickup's tailgate down or off actually does the opposite most of the time, said Kevin Cooper, a researcher at the National Research Council (NRC) of Canada, who has spent more than 35 years testing the aerodynamics of countless vehicles and other structures in NRC wind tunnels.

Cooper demonstrated that the tailgate-down myth was just that - a myth. Back in 1999, in between other tests in NRC's 9m wind tunnel in Ottawa, Cooper studied the aerodynamics of different makes and models of pickup trucks.

His team's tests included trucks with different box lengths. They found that the shorter the box, the worse the drag becomes when the tailgate is left down or removed.

While lowering or removing the tailgate on trucks with an eight-foot long box may decrease the drag by a small margin (less than one percent), lowering it on a six-foot cab - like those typical of crew-cab trucks - increased the drag by five percent. Using a mesh tailgate cover raised it another five percent or more.