so, do you get better mpg's with the tailgate up or down?

[brdhntr]

i've always been told down, but saw a mythbuster rerun that said up is the way to go. f course covered does best, but i'm wondering what real world experience you guys have had with the mj. in all the fullsize trucks i've driven, it didn't seam to matter, but i rarely travel with an empty bed. i haven't done much road travel with the mj yet so i haven't figured it out yet.

 

just curious. :dunno:

[MiNi Beast]

city drive with down

highway drive with it up

[Pete M]

Trucks are apparently more aerodynamic with it up.

 

Plus, if it were any other way, you know the OEMs would offer auto-dropping tailgates to squeak out that last bit of mpg on their behemoth gas-guzzlers. :D

[brdhntr]

Plus, if it were any other way, you know the OEMs would offer auto-dropping tailgates to squeak out that last bit of mpg on their behemoth gas-guzzlers. :D

 

 

 

:agree: that's a very good point. anything to meet the new mpg standards.

[mvusse]

Aren't pickup trucks excempt from the mpg standards?

[Geonovast]

I know that the Mythbusters can't be exact about everything, but from their testing they found you get better mileage with it up. It creates a "vortex" of circulating air in the bed, so there's much less wind drag.

 

Even if I got better with it down, I'd still leave it up because I'm too paranoid that it'll bounce around and somehow pop off.

[89eliminator]

I know that the Mythbusters can't be exact about everything, but from their testing they found you get better mileage with it up. It creates a "vortex" of circulating air in the bed, so there's much less wind drag.

 

Even if I got better with it down, I'd still leave it up because I'm too paranoid that it'll bounce around and somehow pop off.

:agree:

[BLHTAZ]

Yea...it's a myth. There were some folks a few years back that did some testing on the Daytona Internation Speedway and found that there was only a difference of about .5 mpg at speeds over 80 mph.

[Wildman]

Man.....this comes up like every spring :hmm:

 

There was some testing done back in the late 60's at Calspan (sorce) for the auto industry, and it was proven that the tail gate UP created the vortex for wind draft.

 

Try your own test, place a plastic shopping bag in the bed, with the tail gate up, and drive around, see how long the bag stays in the box.

 

Then try the bag (or another one) with the tail gate down, and see how long the bag stays there.

 

I know, it's almost like the myth busters test.

 

My vote goes for ............Tail gate up :D

 

Plus.......every time I'm on the highway, and some one passes me with the tailgate down..... :shake:

[beaterjeep]

To further add proof to this, think about driving in winter; where does the snow accumulate after driving around with your tailgate up? At the front of the bed, closest to the cab. The wind circulates off of the taligate and pushes on the back of the cab just enough to make an improvement in gas mileage. YMMV however.

 

 

(Yes, that was a lame pun, but it applies quite well in this situation :dunce: )

[CEThomas]

You need to drive with it down for 2 tanks and up with 2 tanks and see what you get. Then if you get better get a tonneau or rear net.

 

Have had several pick-up over the years and found 2 that got better with the tail gate down. Both were full size and short beds.

 

88 Ranger long bed = no difference

92 GMC 2500 short bed = 2gal difference - got a tonneau cover

93 Dakota short bed = no difference

96 Ram 1500 short bed = 4 gal difference - got a cap and lost 1 mph

99 S-10 short bed = no difference

00 F-150 short bed = no difference

93 Ranger Super Cab short bed = no difference

89 MJ = have not checked

 

The Ram was the one with the most difference. Around home it's about 70/30 with most being open road ( Wildman can tell you :D ). Did make a trip out to NJ with it to pick up a engine once and drove out with the gate down on the way out and with it up on the way back. The only difference the 305 in the bed and took almost 3/4 of a tank more on the way back :hmm: and no we had no headwind blowing to drive into :yes:

[wolfpackjeeper]

Tailgate up. It creates the same phenomenon as a wing does to control flow separation. Ie, increases the turbulant flow allowing the air to flow over the truck better. We talked about it in class one day when I was in college, newer rally and race type cars are starting to come with small triangles on the roof in a line, they do a similar thing of breaking up the smooth air in order to allow it to flow quicker. This is not the best explanation, but much more and I have to start using words that are not in common usage and math.

[comanche87]

[dasbulliwagen]

I remember reading an article in motor trend in the mid-late 80's where they were testing this. I think it was on an s10 or a gmc equivalent, they tested if it was better with tailgate down, tailgate up, and tonnau cover. I think they came up with tailgate up, but then continued and found that adding a wing on top of the tailgate helped even more. It was a very interesting article. Yes as you said, this topic comes up every so often, and has been researched many times.

[vaquaro]

My $0.02 , I,ve found no difference ,gate up or down ,or with tonneau cover (10% mpg claim is BS ) although if your using a cheapy cover with Velcro you can see the wind pressure tear the tailgate Velcro apart at highway speeds . I've overcome this by spacing the cover bows towards the rear with one about a foot from the tailgate to eliminate the "pocket" forming and over-stressing the velcro closures . :brows:

[BREEZE1]

YALL HAVE TAILGATES?????!!!!! :huh???: :dunce:

[mvusse]

I do believe that's a tailgate.

 

[Geonovast]

YALL HAVE TAILGATES?????!!!!! :huh???: :dunce:

 

I have 3.