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Hot Rodding Magazine this month has an article showing lowering the tailgate may endeed lower your mpg because it removes the "air bubble" created when the gate is up. The air bubble in the cab area serves to let the air rom the roof ride smoothly off. This was the conclusion of a study done at the Unoiversity of Michigan.
 

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I have heard and seen studies claiming both ways . If you do leave your tailgate down DO NOT FORGET ITS DOWN WHEN YOU BACK UP !!!!! I have seen several people crunch there tailgates because they forgot . :banghead:
 

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I have to agree with their conclusions. I've run my truck both ways and have gotten 1-2 mpg better with the gate up.
:crazy:
 

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I have made trips around town with it up and down and I don't see 1 single difference....oh ya I have a hard cover :)


sry I had to :)
 

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My coinholder adds 15 HP!
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I drove back home 100 miles with it up then put it down for the drive back and noticed a .2 increase. Not even worth the effort of putting it down in my opinion.
 

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I was wondering the same thing. I drove around for about a month without my tailgate, and my mileage actually got worse. I didn't understand it. I might have to try this at the track now and see what happens. I have always run with the tailgate down.
 

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My time slips at the track are consistantly .1-.2 seconds faster with the tailgate UP. My times did get quicker when I removed the tailgate+spare tire.... but I think that was the removal of the weight that gave the increase not the aero dynamics... In my opinion there is NO gain to be had by lowering the tailgate on my truck.

SPEED SAFE, AIR RAM
 

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C HEMI GO
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You have to realize that with the gate up, the air inside your bed is largely stagnant (stuff blows around, but its mainly just whirling in place.) This means the drag on the back of your vehicle caused by turbulence is divided into two small areas: The back windshield area and the behind tailgate area. If you notice, newer trucks including the ram are built to where the sides come in a bit as you move towards the back of the truck to help air sweep around the tailgate. This design is nullified if there is no gate or the gate is down. Also, if the gate is down, air coming over the top of the truck has to go straight down behind the cab to fill the tailgate and then blow out the back. You create a low-pressure area in your bed, essentially pulling the truck backwards.

I believe another study posted here stated that for best aerodynamics, remove the bug deflector, get a 4/6 drop, lead the tailgate up, and get a tonneau of possible. Bed caps cause the same low-pressure turbulence area.
 

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The Legendary Cross Ram
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It would be my guess that a truck with a long bed would get worse mpg with the gate down when compared to the same kind of truck with a short bed.
 

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Daniel Hice said:
I have made trips around town with it up and down and I don't see 1 single difference....oh ya I have a hard cover :)


sry I had to :)

The hard cover is the reason for sure. I have
noticed better MPG since I had my SnugLid SL
installed.
 

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mope
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Does Removing the bug deflector actually help mileage? If so I'm ripping mine off.
 

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AIR_RAM said:
My time slips at the track are consistantly .1-.2 seconds faster with the tailgate UP. My times did get quicker when I removed the tailgate+spare tire.... but I think that was the removal of the weight that gave the increase not the aero dynamics... In my opinion there is NO gain to be had by lowering the tailgate on my truck.

SPEED SAFE, AIR RAM
I need to leave my spare and tailgate on for traction, so I definately need to try this the next time I'm at the track.
 

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The Legendary Cross Ram
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the75powerwagon said:
what about a net?
My guess would be that it would affect your mileage as if your tailgate were down.
 

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Honestly I can not say the cover did ANYTHING for my fuel economey. I really am not impressed with my investment which I did mainly for the fuel economey than the looks... I do like the looks but if I didnt think it would help I would not have purchased it... So all in all I dont feel the cover has done ANYTHING for my truck... if it did it was so minute that it was un noticable to my driving. So If your thinking about getting a cover for the looks... I say go for it... if you think its going to make much of a difference if any at all with your fuel economey I would not get too excited about it because It didnt for me.

So far the mod that got me the MOST MPG was removing the 20"s and installing the 17's, 4.56 gears, A/R Cold Air Induction system, removing the clutch fan (installed electric fan) and installing the J/S scoop....each of these made a noticable differnece in increasing fuel economey.

Leaving the tailgate up seemed to give better fuel economey when i tried it over a year ago... I did it for a month with it down then back up... it was a small difference but I felt it was better with the tailgate up.

SPEED SAFE, AIR RAM
 

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AIR_RAM said:
Honestly I can not say the cover did ANYTHING for my fuel economey. I really am not impressed with my investment which I did mainly for the fuel economey than the looks... I do like the looks but if I didnt think it would help I would not have purchased it... So all in all I dont feel the cover has done ANYTHING for my truck... if it did it was so minute that it was un noticable to my driving. So If your thinking about getting a cover for the looks... I say go for it... if you think its going to make much of a difference if any at all with your fuel economey I would not get too excited about it because It didnt for me.

So far the mod that got me the MOST MPG was removing the 20"s and installing the 17's, 4.56 gears, A/R Cold Air Induction system, removing the clutch fan (installed electric fan) and installing the J/S scoop....each of these made a noticable differnece in increasing fuel economey.

Leaving the tailgate up seemed to give better fuel economey when i tried it over a year ago... I did it for a month with it down then back up... it was a small difference but I felt it was better with the tailgate up.

SPEED SAFE, AIR RAM
Nick...Since that cover didn't work, do you want to sell it to me?
 

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LOL ... Well I have it now .... So I will leave it in place. BUT I would not buy one for feul economey again.... that was my main reason for the purchase. But it does look good and the ability to LOCK the bed is a nice feature...

SPEED SAFE, AIR RAM
 

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AIR_RAM said:
LOL ... Well I have it now .... So I will leave it in place. BUT I would not buy one for feul economey again.... that was my main reason for the purchase. But it does look good and the ability to LOCK the bed is a nice feature...

SPEED SAFE, AIR RAM
Darn...I figured it was worth a try!!
 

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I bought my cover more for storage and security above all else. I think it looks great and being able to store stuff is awesome. I figured if I saw any mpg improvement it would just be a bonus anyway.

KB
 

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I've found the same results for 2nd generation Rams too.
6.5' box and 8'.

One street night at the track we took 2 Dodges and 1 Ford.
The Dodges were both reg cabs. The Ford was a 92 reg cab 8' box.
Both Rams faster and quicker with the gate up, minor but consitant. The Ford had the opposite and most dramatic change. A full mph increase with the gate down.

I don't remember the other trucks times exactly but the Ford was a 5L with a 5 spd and 3.08's, 4000lbs. Ran 17.0 @ 80mph.
The 95 long box 5.2 auto, 3.5's, 4800lbs. 16.9 @ 80
My 95 Sport short box 5.2, 5 spd, 3.5, 4600lbs. [email protected]
 
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