Better Truck mpg with the tailgate off?

[PocketThunder]

Is it true that i will get better fuel economy with the tail gate off of my truck?  The guys at work said that they proved it to be false on Mythbusters one episode but i havent seen that one yet.   I'm going to try and drive the same speed for two tanks of gas, one with the gate on and one with the gate off.  I'll post my results in two weeks.

Paul
in St. Paul

My truck "Whitey" gets about 14 mpg in the summer time.  '89 Ram W250 reg cab, long box, 318, 4-speed.

[Old Moparz]

I have heard the same thing for years, that you'd get better mileage with it off. I would think it would be a very small difference if any, but probably wouldn't be noticeable at all unless you did a lot of long highway miles commuting. The same goes for a tonnau cover, or cap/shell on the bed. Drag from the wind has to account for something, a lot of tow vehicles put deflectors on the roof so they can direct the airflow over the trailer or object being towed.

Couldn't hurt to try it, but you'd have to duplicate the conditions pretty accurately.

[adauto]

You ever see that TV show "Mythbusters"?? They did their thing onm this a few weeks back. Their show showed better gas milage w/tailgate up. On of my emplyees drive a Dakota he leaves his gate down all the time. So I don't know who to belive

[Arthu®]

I would think that that would be different from truck to truck. It has a lot to do with how the airflow is going up the windshield and over the car. I would think that with modern trucks that would have thought about this and made it so that the drag behind the cab reaches to just over the tailgate on highwayspeeds so that the air doesn't catch the tailgate. If it would it would most definitly help to keep the tailigate down, otherwise I don't think there would be that much of a difference. But I am by no means an aerodynamics expert.

Arthur

[BigBlockSam]

proved it to be false on Mythbusters one episode   

[Todd Wilson]

A college engineering class did this several years ago in a wind tunell and had pictures to show what they found.   All the newer trucks did better with the tailgate up. The tonneau (how ever you spell it) covers did better and the full toppper does even better yet.  The air seemed to go up and over and right off the back of the truck. With the gate down it disrupted the flower and caused turbulance.  I think make 35+ year old trucks it might make a different according to aero dynamics but those engines and gears they had probably wouldnt show a MPG increase.

Keep your tailgate up!   



Todd

[hemihead]

I can't believe people worry about this topic lol 

[TruckDriver]

A college engineering class did this several years ago in a wind tunell and had pictures to show what they found.   All the newer trucks did better with the tailgate up. The tonneau (how ever you spell it) covers did better and the full toppper does even better yet.  The air seemed to go up and over and right off the back of the truck. With the gate down it disrupted the flower and caused turbulance.  I think make 35+ year old trucks it might make a different according to aero dynamics but those engines and gears they had probably wouldnt show a MPG increase.

I heard that too somewhere. Trucks are designed to have the tailgate up. Having the tailgate up will also improve your traction in rain and in snow.

[Charger_Fan]

You know...if you just prop your tailgate open at say a 45* <---(how do ya do degree again?) angle, you'll have a factory rear spoiler!

[chrisII]

on my 94 dakota it makes a pretty big difference on the hwy at 75-80. if youve got a sliding rear window and you open it up have you ever noticed how all the crap flys in at you? this is cuz the air is bouncing off the tailgate, puting it down or taking it off lets out the air that gets trapped.

[The Ghoul]

 
My uncle has a new ford f-150. He decided that he would get better milage with the gate down.
So he did.
He didnt bother to put it back up and lock it when he went into stores and such.
Some one stold his tailgate.
Turns out they are hydrolicly assisted.
about $2k later he had the tailgate replaced...
all to save a couple of miles per galling (wich he didnt because of what the mythbusters stated and he confermed).
new trucks are designed to created an air pocket in the bed wich basically 'pushes' the air over the tail gate. 

[PocketThunder]

You know...if you just prop your tailgate open at say a 45* <---(how do ya do degree again?) angle, you'll have a factory rear spoiler!

Hold the ALT key down and hit 167 like this  45º   

Whitey is too fast as it is i dont want to encourage him any further....

[Charger_Fan]

You know...if you just prop your tailgate open at say a 45* <---(how do ya do degree again?) angle, you'll have a factory rear spoiler!

Hold the ALT key down and hit 167 like this  45º   

Thanks Man, this time I'm writing it down.

[is_it_EVER_done?]

Chrysler Corp did wind tunnel and road testing on this when they were developing the "Mack" style truck and found that the gate up was better by a few percentage points.

[bull]

I can't believe people worry about this topic lol 

I can't believe people worry about people who worry about this topic. lol 

[greenpigs]

Its hemihead thats about says it all.

[Old Moparz]

I have to say this topic is right where it belongs & makes for an informative read. Some people don't care about MPG, but some do. Personally I don't lose sleep over it since I get gasoline where I work, & don't look at prices when I am on a trip & have to fill up. It's always good to learn things & this topic has learned me something good. I can now make a degrees symbol. 

                                  Tailgate at 90º    (very cool!)

[BigBlackDodge]

At close to 3 bucks a gallon, it's a great topic!

Saw the mythbuster episode a while back. The tail gate up truck went farther than with it down.............plain and simple test.


BBD

[PocketThunder]

It's always good to learn things & this topic has learned me something good. I can now make a degrees symbol. 

                                  Tailgate at 90º    (very cool!)

[Chargen69]

What Mythbusters proved was, that when the tailgate is up, there is a "bubble" of air that gets trapped in a circle in the bed of the truck, that makes all the air coming over the truck bounce over the air bubble, creating less turbulence(sp),  With the tailgate down, air comes over the truck and heads straight for the bed, producing downforce and turbulence.

[Arthu®]

What Mythbusters proved was, that when the tailgate is up, there is a "bubble" of air that gets trapped in a circle in the bed of the truck, that makes all the air coming over the truck bounce over the air bubble, creating less turbulence(sp),  With the tailgate down, air comes over the truck and heads straight for the bed, producing downforce and turbulence.

Thanks that actually made sence

[twilt]

I dont think the people driving behind me would appreciate it if i drove around with the tailgate down on my truck.