hello,

I'm not sure what area of the site to ask, so I'll ask here.

(and i know it sounds like a dumb question...but I gotta ask)

I always thought tailgate down allows better gas mileage. Then the other day a friend of mine said he read in a truck magazine that the tailgate up is better for gas mileage!!!!

So which is it???

(I did search this site and found a couple people say down is better...has anyone else read that up is better?)

-hpip

 

I know for a fact that you will get better mileage down and worse gas mileage up.

The only reason I can say this with any degree of certainty is that you are driving an Expedition.

 

your attention to detail is phenominal... but I just picked up a 'pickup' this weekend...hence the question

 

I don't have a link or anything, but I've read many times and in many places that tailgate up is better. I used to believe that leaving the tailgate down helped, but last September I took a 4K mile road trip to Colorado and back (435 miles across Kansas is the most boring country I've ever seen). I had the tailgate down while driving out there but needed to put the tailgate up on the return trip to secure a couple items. Driving 100% interstate at the same speeds (cruise control), I averaged 2 mpg better with the tailgate up. I checked at every single tankful and kept a log to eliminate any variances and to confirm my results. I was also very careful to set my cruise at the exact same speed since a few mph can kill fuel economy.

 

Rocky--Did you forget to factor in the effects of the hills. Going out you were generally going up hill and coming back you were going down. I do assume you went form Florida to Colorado.

With that said I have read that the up position is better. The reason cited is it basically causes a cushion of air in the bed. The wind hits the tailgate and swirls, causing excess air to flow over the box instead of in it. A while back I believe someone had done research on this and made a replica of a truck and placed it in a wind tunnel with the smoke. That person is the one who stated the air formed a cushion.

 

found this on epinions.com



The truth About Truck Tailgates
According to a "Tech Tidbit" item in the September 2004 Road & Track magazine (page 156), it is generally better to keep your pickup truck tailgate up instead of down or removed. It seems counter intuitive, but research by the National Research Council of Canada determined that there was generally a lower drag coefficient (Cd) with the tailgate up than with the tailgate down or removed.

The difference wasn't big but it was measurable, with a 2002 Ford F150 Crew Cab measuring a Cd of 0.5304 with the tailgate up and 0.5425 with tailgate down. With the tailgate removed, the Cd was 0.5596. However, placing a tonneau cover on the bed lowered the Cd to 0.4967, probably enough to offset the weight of the tonneau cover if you do much highway driving.

Although not mentioned in this brief item in Road & Track, there's another good reason to have your tailgate up and latched: It adds to the structural strength of your vehicle.

 

I knew someone would mention this. If I made that elevation change in 100-200 miles, I could see your point. But with the constant up and down elevation changes through 11 states and 2000 miles I do not see where it would be a factor. Do you know the elevation changes from one end of Kansas to the other? I had 500 miles of corn fields each way with no major elevation changes, but my mileage was 2mpg higher with the tailgate up during that stretch. Do you want to factor in the 6 hours of pouring rain I had on the return trip? Gimmie a break.

 

Dont know where I heard it but I heard up is better. It had something to do with the low pressure pocket of air in the bed of a truck at speed, Like when you see a can or a cup floating around in someones bed on the highway and it never blows out...

Kind of like the dimples on a golf ball I think

 

Anything up is better!

 

The Kansas Department of Tourism thanks you for your positive review.

Did you stop and see the 8,000 lb prairie dog in Oakley?

 

Since we're getting rude this is my last comment. Your cross country trip with the tailgate up and the return trip with the tailgate down is irrelavant. The tempurature was different both times as was the GENERAL slope of the land. Yes you did go up and down hills but I'm sure when you stoppped in Colorado you were higher than the 345 feet max elevation in Florida (assuming that's where you started). The wind I'm sure was not the same each way either. The two trips can not be used as comparables since there are way too many varibles between them to accurately state whether the tailgate up or tailgate down has any affect.

 

The real world answer is why did they do such a radical body style change in 1997?

Wind tunnel testing, period.

They redesigned them to have better aerodynamics with tail gate up. One of the major reasons the Supercrew came out the shortest beds until lately.

So, the answer to the question would be once again another question. What year is your truck?What model?

Fuzzy math at it's best!!!

 

I vote for running with it up. Whether or not it makes a MPG difference doesn't matter. Running with it down, it will only be a matter of time until some stupid soccer mom in a minivan slams into the back of it.

 

I vote everyone should run with it intact and up! It is scarey when you see Festus Joe Bob running down the highway with his tailgate down or off and he has a spare tire some rusted bolts he probabley can't even remeber what they came out of and a beat up tool box that has obviosley slid across the pavement on more than one occasion. Add the for mentioned structurial integrity, the minimal amount of noticeable change either way, and the saftey factor all together and the answer is obvious for me.

2+2=7.2547777






















Now what a minute..............





Finger 1


Finger 2


Finger oops forgot I cut that one off....

Finger 1
Finger 2
Finger 4
Finger 7
+ the nub
yep thats it.....






.....Naw that ain't right!

Is it?
--------------ley slid across the pavement on more than one occasion. Add the for mentioned structurial integrity, the minimal amount of noticeable change either way, and the saftey factor all together and the answer is obvious for me.

2+2=7.2547777






















Now what a minute..............





Finger 1


Finger 2


Finger oops forgot I cut that one off....

Finger 1
Finger 2
Finger 4
Finger 7
+ the nub
yep thats it.....






.....Naw that ain't right!

Is it?

 

I have personally tested this theory and found down is better on mileage on my trk but i have a tonneau cover so its up all the time, especialy if your hauling something. I'm embarassed to say.