[Shackleford]

In the following video the Mythbusters examine the following modifications to a truck's bed to see how it affects the truck's MPG:

1. Tailgate up (control test)
2. Tailgate down
3. Hard top tonneau
4. Mesh tailgate
5. No tailgate

Oddly enough, the truck used in the test is Jamie's trusty Dodge Dakota (de-badged... I guess Dodge didn't want to pay for any advertising!)

http://www.youtube.com/watch?v=r3aqHbD-O9E&feature=related

Here are the results:

WORST: Tailgate down
BEST: Mesh Tailgate (a little more than 5% savings)
All of the rest were relatively the same, and having installed a tonneau recently I can confirm the lack of an MPG boost.


MORAL: If you're buying a tonneau for the sole reason of improving your MPG you're wasting your money. It seems like there's a lot of MPG improvement myths when it comes to vehicles, but this one is especially bad because tonneau-cover MPG improvements seems so intrinsically plausible. The bed just seems like a massive wind catcher!

This also shows that you shouldn't trust any manufacturer's claim on MPG improvement. With the internet, it's trivially easy to verify their claims so spend 15 minutes before spending a few hundred dollars on snake oil. Perfect example for me is the Throttle Body spacer. They supposedly improve MPG, but a quick search on the web told me (for the types of engines in a Dakota) that this really is a big scam.

Oh, and always be skeptical of perfectly nice round numbers! Many tonneaus claim a nice, neat, and perfect 10% improvement.

 

[SmoovC]

I'm hearing you on that; a tonneau cover didn't do anything for me mileage wise either. Thanks for posting the info!

 

[axax]

why would mesh be better than no tailgate??

 

[72 FOWLER]

soft tonneau?

why would mesh be better than no tailgate??

Good question...

 

[Shimrra]

mesh is better becasue it traps SOME air, still creating a small pocket to help with drag, but it also allows the air to pass without stopping. so it's like gate down without the friction. kinda.

and i always knew the hardcover MPG improvements were BS. take any truck. put some micky d's wrappers in the bed and then open the back window at 60. THEY HIT YOU IN THE FACE. aerodynamics have some funny shit lol

 

[hskrRT]

Modern trucks are designed in wind tunnels to maximize aerodynamics. As mentioned, with an open bed, it creats a low pressure area which more or less causes the air to flow right over the bed with minimal restrictions. Mythbusters aren't the first to do this type of testing. I bought a tonneau cover to be able to secure stuff in my bed and for looks. MPG had nothing to do with it. And even if it did help, once you factor in the price of the tonneau, it would take longer than most people own thier truck to make up the cost of the tonneau in fuel savings.

 

[Shackleford]

Modern trucks are designed in wind tunnels to maximize aerodynamics. As mentioned, with an open bed, it creats a low pressure area which more or less causes the air to flow right over the bed with minimal restrictions. Mythbusters aren't the first to do this type of testing. I bought a tonneau cover to be able to secure stuff in my bed and for looks. MPG had nothing to do with it. And even if it did help, once you factor in the price of the tonneau, it would take longer than most people own thier truck to make up the cost of the tonneau in fuel savings.

That's because most people have Chevys, Fords, and import trucks instead of Dakotas. Of course they're going to sell their truck in a few years! Duh!

 

[axax]

put some micky d's wrappers in the bed and then open the back window at 60. THEY HIT YOU IN THE FACE. aerodynamics have some funny shit lol

put anything, paper, bags, disposable plates whatever you want

they float in the back, looks really funny, and if the back window is open it all flies in and hits you in the face just to teach you not to put trash in the bed to make it fly off behind you with the back window open...

 

[gocartone]

I haven't noticed any change in MPG with my truck since I took the tonneau off, did make it quicker losing the ~150lbs it weighed though, big thick heavy SOB.

 

[axax]

I haven't noticed any change in MPG with my truck since I took the tonneau off, did make it quicker losing the ~150lbs it weighed though, big thick heavy SOB.

plus this is just what I think, it looks better without the tonneau and your bed is now useful

Ive always been into those folding or roll up soft covers though

 

[Rebel13]

was alright result i guess. tests where still a :fail2:

 

[ADakotaRTGuy]

plus this is just what I think, it looks better without the tonneau and your bed is now useful

Ive always been into those folding or roll up soft covers though

I love my tri-fold extang cover, its the shizzle.

 

[gocartone]

plus this is just what I think, it looks better without the tonneau and your bed is now useful

Ive always been into those folding or roll up soft covers though

Oh I think the same thing, mine has a thick tonneau that sits about 2-2.5" higher then the top of the bed. Everytime I wanted to haul my quad it was a two man job to take it off and put it somewhere. I would like a roll-up one, but not for how much they cost. I keep a 6' heavy duty locking cable in the back if I ever need something to not get stolen.

 

[silverback]

My Quad cab has the tailgate down most of the time and with my driving habits, gets better gas mileage vs. tailgate up. When it is up, I can feel the drag being created. Maybe the longer cab and shorter bed make a difference.
I'm curious as to what the Mythbusters findings would be with a Quad cab...

 

[01Motorsport]

My situation is a slightly different twist, since my Dak has a Snugtop cab-hi shell. It doesn't hurt or help the mpg. The shell itself weighs 160 pounds, which helps the traction considerably. It's aero-friendly enough (with the Texas Tail wing) that it rolls along on Interstate @70mph+ without a ripple. The Dak is absolutely rock solid when passing 18 wheelers or in cross winds. It's a work truck with an alter :woot: ego, anyway.

 

[Shackleford]

My Quad cab has the tailgate down most of the time and with my driving habits, gets better gas mileage vs. tailgate up. When it is up, I can feel the drag being created. Maybe the longer cab and shorter bed make a difference.
I'm curious as to what the Mythbusters findings would be with a Quad cab...

Did you watch the video? They were very angry over the feedback over their original test. I think if you asked they'd hunt you down in the middle of the night and kill you! :jester:

 

[Shackleford]

Oh I think the same thing, mine has a thick tonneau that sits about 2-2.5" higher then the top of the bed. Everytime I wanted to haul my quad it was a two man job to take it off and put it somewhere. I would like a roll-up one, but not for how much they cost. I keep a 6' heavy duty locking cable in the back if I ever need something to not get stolen.

Having had both, I can definitely say I prefer this rolltop version the best because it's so much more versatile than the hardtop. The hardtop did have an advantage in that I could secure things a couple inches taller than my current rolltop tonneau, or even if it couldn't close I could lay it on the top of whatever was in there and at least protect it from the wind or falling out. Depending on how far closed it got it could even either give the illusion that the bed was locked.

Overall this rolltop tonneau is far and beyond superior to the hardtop tonneau I used to have.

 

[ecdak]

very interesting mythbusters.

 

[Rebel13]

Here are some points:

First off those test where bogous, not same route temp wind dew etc.

next hard tonnaoh is lot heavier then without one, so obviously weight isn't considered.

Soft tonnoh was never tested, neither was a grandpa one- full lenght cap and some with the added ended cap.

Go all out or don't waste time. Mythbusters is full of shit half the time anyway, bunch of stupid ass acting!

 

[DrPepper]

The only reason I have a soft cover is....

1st: It looks better and 2nd: it makes it harder for some dip to use my bed for his trash can...!!! :jester: