Like everyone else crying over fuel prices I am trying to save every way that I can. I have already swapped out for a cold air intake, bought a programmer and now I am looking at exhaust. The next item I was looking at was a hard cover for the bed. Looks like to me it would definitely cut down on the air drag and improve mileage. Has anyone had any luck with this. I know I used to say a truck is for hauling and a real truck doesn't need a cover but times are getting tight at the pumps!  

Tonneau will make a small difference, but it won't be dramatic. There's another thread on this forum that talks about the benefits of a tonneau. You might get a 1 mpg difference with the tonneau alone. Anyone else have any before/after stories on fuel economy with a tonneau?  

i have a cover on the back of my truck. a lorado. it's super nice. the supports roll up with the cover. and it stays nice and dry in the box. i see about a 1.5 mpg difference if it is covering the box.