yeah i remember my friends telling me they did something like that on mythbusters i may have gotten the results mixed around or something..i never actually saw that episode though

 

I saw that Mythbusters episode... and I love those guys, but I mean, this is truly one of those cases, that "your mileage may vary."

I think the tailgate up/versus down might hold true across the board. The tailgate missing, being better than on/up... meh? maybe? Cover... I think that is a case of the aerodynamics of the truck (or lack thereof). The dakota they used, is certainly more aerodynamic than today's 1500s, and definitely more than my 2500 (a brick with a hemi).

I think it is truly one of those things that you have to try it out yourself, under controlled conditions ON YOUR TRUCK, and find what works. Either way, at best you might get 1mpg out of your tweaks.

Me? I get 12.5mpg calculated, and by computer give or take .5 mpg... Haven't tried cover (don't have one), and haven't tried removing the tailgate. But at 12.5 mpg... um... I am not expecting to get like 30 outta it anyway.

My own 2001 Dakota 4x4, with 4.7 liter... Um... got 19mpg highway, up/down/cover or not... didn't matter.

I put 160,000 of MY OWN MILES on it, driving to work 60 miles one way. Trust me that truck I am sure of... I will post back if I wind up driving this truck more than once in a while to work.

 

Yea I heard about that mythbuster show too. That stopped me from riding with my tailgate down lol.

but the reason I said a 20% increase is that most companies that make tonnaeu covers advertise that number. Some more. Sounds too good too be true. And it looks like it is.

 

No noticable gain here, however, I like the clean look.

 

they tested with a short bed the better gas myth was for teh long beds
on a diffrent place the guys were saying that they were getting better mileage w/ their long beds

 

aerodynamic improvements
help more and more
as speed goes up

A tonneau typically reduces the drag of the wind
by about 10%
which at typical 65 to 75 mph speeds
gives a MPG gain of about 5 to 6%

If you were to drive 100 mph
the MPG gain might get close to 20%

Here is a 45 mph test of tonneaus at a racetrack
where the 45 mph limit was because the vehicles had no rollbars fitted.

http://www.sema.org/main/semaorghome.aspx?id=55785

an independent review of the same test done above

http://dieseltruckworld.tenmagazines...ticle&aid=2835

other tonneau links:

an award winning student project on a 2nd Gen Ram model:

http://web.archive.org/web/200304142...er/Tonneau.htm

Ford engineer says 5% gain with tonneau:

http://web.archive.org/web/200611221..._save_fuel.htm

Past aerodynamic testing has found that most of the gain of a tonneau is because the last 3 feet of the cargo box of the pickup truck near the tailgate is covered. If you don't want a full tonneau and want the MPG gain, cover just this rear section, or buy some plastic boxes with snap on lids that are the right height to come up to the top of the cargo box that you can keep secured near the tailgate. A side benefit of such rear boxes is that in winter you can add weight to them for increased ice/snow traction.

 

You guys are forgetting another benefit of a tonneau cover - keeping the bed clear. For us guys that live where it snows it sure is a lot easier to brush 8" of snow off from the cover rather than shoveling it out of the bed or pushing it out of the gate. A good load of snow in the bed can be a lot of weight added = lower mileage.

 

One of the main reasons I got mine

 

In my 2005 1500 QC Hemi 2x4, I can get as high as 21mpg, between 60-70, I have a hard tonneau, not sure if it has alot to do with it as I bought the truck with the tonneau on it, and have never had it off for a comparison.