I have an 04 2500 HD crew cab that gets 9mpg (HWY)and i have a leer shell on it. I was wondering if anyone would know if i would get better or worse milage if i switched it out and tried a roll up tonnaeu istead?

thanks.

 

The shell usually improves gas mileage but not by much or if any. We have also seen in decrease as well, but major studies from numerous universitieshave proven that a tonneau cover is the best way to improve gas mileage. We didour own test a few years ago on our 04 f150 for ****z and giggles. Truck has 2/5 drop, 22's, magnaflowcat back, trueflow intake, and a edge programmer. Now we only tested this mostly at highway speeds. Same trip route and pretty much the same conditons.A 165 mile round trip. 3 weekend trips to the casino.

Stock no cover : 16.4
Leer 100xq Camper Shell: 15.9
ARE LSX Tonneau Cover: 17.6
Truck gets about 13.3-13.9 in town according to the edge and info center with the tonneau not sure what it was with the Leer........

 

ever watched mythbusters where they proved that NO cover, or driving with tailgate up and open truckbed, is the best for mpg? due to that air vortex created in the bed that breaks drag?

for the practicality sake, flip covers are the most utilitarian ones.