Do Tonneau Truck Covers save gas?

I’ve been out of school for a long time, and I pretty much sucked at physics when I WAS there, but …

Consider this … the empty bed of a pickup creates a resistance. If the truck is moving forward, the air is flowing up over the hood, over the cab, and down …. the air moves back until it encounters the tailgate. The tailgate essentially “stops” the natural flow of the air.

I would have to assume that this would create “drag” which would, in turn, affect gas mileage.

A tonneau cover creates a flat, smooth surface over the bed of the truck. It eliminates the “barrier” that would be created by a tailgate. The air would flow smoothly over the tonneau cover, encountering no resistance or “drag” … so I’d have to think that gas mileage would be improved.

ADDED: I think a “cap” type of cover … one that is the same height as the cab of the truck … would be best, aerodynamically. A tonneau would be better than an open bed, but I imagine that a cap-type covering would facilitate airflow more effortlessly over the vehicle than any other type.

Unfortunately this is an urban legend. Tonneau covers increase drag. However they do keep prying eyes off the contents of your truck bed, which is an excellent reason to own one.

Normally, air traveling over your truck will get caught by the tailgate, this air will continue to circulate through the bed, creating a cushion or pocket of air that air coming over the cab travels over, making the aerodynamics similar to a passenger car’s construction.

Adding a tonneau cover eliminates this pocket of air, and the air coming over the cab top will drag on the back half of the cover, this will hurt fuel economy.

yes this will increase you gas milage by 2 or 3 miles the same thing happens if you just take off your tale gate.

yes, it does. It increases mine by almost 5 mpg on the interstate. The effect is much less on city streets where you will drive slower.

it worked for me gained3 mpg

Hell yea, This site has an online tool to figure out how much you will save with a Tonneau cover

http://tonocover.com/Tonneau-Covers.htm