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Do not put tailgate down to save gas...

amoraamora Posts: 204
edited April 2014 in Toyota
I ve seen many pick-up trucks on freeway with
tail gate down. THIS IS NOT GOOD, CAN WEAKEN
HINGES, also there is no MPG improvement, you
aeronautical and engineering buffs would know
this. A Vortex is created at rear of cab,
trapping the air.

A toneau cover will do the trick.

TO ALL TAILGATERS: Stop using your tailgates to
save gas. If you claim you are getting better
MPG, recheck your math.....


  • eharri3eharri3 Posts: 645
    It may also be unsafe if the thing slides off in traffic. If you want to experiment and find out for yourself, take the it off completely... on most newer trucks its easy, requires no tools
  • kit1404kit1404 Posts: 128
    I haven't seen anyone driving with the tailgate down in years. And, actually those net-things aren't so popular either anymore. Have you ever watched a full-size truck on a really bad, rough road without the tailgate - the fenders start to vibrate some. The truck needs the support of the tailgate for the bed to be properly supported, unless you got a heavy load and/or a big camper in the back and that seems to settle things down. Just don't do it. Think about body on frame construction, springs designed to bounce without a good load and the other things that support other things. It won't help anyway with your mpg. Plus, you could lose your tailgate if you leave it down - that part seems to depend on the manufacturer's design. I see signs on my road with people looking for tailgates that fell off for whatever reason!
  • obyoneobyone Posts: 8,054
    with no tailgates at all. And with people sitting in the bed....nuts.
  • modvptnlmodvptnl Posts: 1,352
    You're totally WRONG!!.......................

    Just kidding.LOL!!!!
  • amoraamora Posts: 204
    Live in So. Calif, drive 78 mi one way to work,
    car pool also. See thousands of cars, trucks
    everyday. See many many trucks with tail gates
    down, mini, full size, in fact saw a F250HD
    reg cab long bed with tail gate down.....INHO if
    (another topic) people want a true economy car then BUY A 1969 CHEVY NOVA WITH IN-LINE 6 from
    wrecking yard, offer $200.00, then rebuit motor for under $300 if you can and you should get
    16 mpg for 10 years. THIS IS TRUE ECONOMY CAR,
    twenty thousand big ones buys lots of gasolene....
  • amoraamora Posts: 204
    roads in windy conditions with tailgate down.
    In So. Ca we have SANTA ANA WINDS that you can feel while driving no matter if driving a HUMMER or YUGO SS...
  • amoraamora Posts: 204
    Long live the DOHC Yamaha alum heads on Vulcan
    cast iron FOMOCO 60 degree block, LOL....
  • obyone,
    Be thankful that they're riding in the bed of the truck. They're just preserving the gene pool for the rest of us.
  • markbuckmarkbuck Posts: 1,021
    My old CC F350 diesel used to get it's best fuel economy during river trips where I had the bed full of rafts and junk, a bunch of canoe's and kyacks on the roof, and running about 60 mph. Figure the boats on the roof really helped streamline the air over the bed or something plus a full bed plus slow speeds.....
  • mledtjemledtje Posts: 1,123
    If you want to improve fuel economy on a PU, add a shell or a tonneau cover.

    It always cracks me up to see trucks with the tailgate down, usually it is a truck with a 6-10" lift and 35"+ tires and suddenly he wants better mileage??

    Mike L
  • oldharryoldharry Posts: 413
    I found that I save a little fuel if I move the seat back an extra notch. Makes me think about it when pressing on the accelerator. :<)

  • I'm 6' 2" and I already have the seat back all the way with the headrest touching the rear glass. Guess I'll have to buy an extended cab and move the entire mounting system back. But that will make for a tight squeeze in the back! But I'll save a bit of gas!
  • Somebody once posted a link to a term paper project on wind resistance and pickup trucks. The students used a Dodge and showed some rather graphic evidence of the air flow over the truck. It seems that the lowest coefficient of drag was obtained with a shell with round corners. I don't have the url but if anyone has the link it is really worth looking at the results of the experiments.
  • amoraamora Posts: 204
    DODGE RAM pickups with the RAM head emblem protruding on hood; "PULL TO SIDE OF ROAD, STOP,
    FACING THE WINDSHIELD" the wind resistance should be somewhat less to the tune of an increase in
    fuel mileage by about .0003 %
  • oldharryoldharry Posts: 413
    maybe if you just took off your right shoe. . . :<)

  • mdecampsmdecamps Posts: 115
    I have a '98 S-10 and do a lot of highway traveling. I gain 3mpg with the tailgate down. You can say what you want, but I have tested this theory time and time again. It's never "fell off" in traffic, either!
  • amoraamora Posts: 204
    Have owned 4 S10s, '87 4X4 ext cab 2.8L, 88 S10 4.3, '91 S10 4X4 4-DR
    Blazer TAHOE 4.3, '00 S10 reg cab XTREME 2.2L.....fuel tank gauges
    are very erratic in these vehicles and therefore a true accurate
    calculation is difficult, approximations are ord of the day....
  • nobody uses the fuel guage to calculate mileage, do they? For the obvious reason that you state, you cannot tell how many gallons you have used by the guage. You can tell though, by refilling the tank all the way and the same way each time -- preferably at exactly the same station and pump so that the vehicle is sitting at the same angle each time and so that the cut off tendancies of the specific pump/nozzle don't vary. Of course, then you use the mileage by either the trip odometer (which you immediately reset after recording the mileage so you can do it again) or, if suspicious of that reading, the regular odometer reading and subtracting from the previous reading. If this sounds painfully obvious, I apologize, but your post seemed to indicate that you didn't think of this method....
  • amoraamora Posts: 204
    Apology not required, I am the one that is sorry I did clarify my
    statement. I have filled the S10 gas tank to the spill level and
    have run mileage checks based on odometer readings and the
    amount of fuel at each fill up (spill level). I have received
    various non consistant readings also including tail gate in down
    position. If I average out all readings they are same with tail gate
    down or up. I have run 500+ mile checks from Los Angeles to San
    Francisco on the infamous Grapevine and highway 5.... the variance
    has always been +/- 2-3 mpg....I also used my HP32SII RPN SCIENTIFIC
    calculator...(mult, divide and enter keys) also pencil and small
    notebook for manual calcs....
  • I see.... ;-)
  • drowe1drowe1 Posts: 5
    At the speeds I drive 80+ usually I always get better mileage. PLUS it is WAY more stable. When the tailgate is up you can feel the bed load up with pressure from the air coming over the cab into the bed. Then when the air pressure gets high enough the air coming over the top just continues over the bed stripping the air away with it leaving a lower pressure area and WUMP! you can feel it hit the bed again. Unsettling! Naturally a cap would be even better but I do not like the look.

    94 Ford Ranger ext cab 2wd
  • Tailgate up-down makes little or no diff. Have tried both ways. Did all the math. The person with the pen and paper, I forget who- did you have a head wind,tail wind? Now that would make a diff.
    A cap might make up 1 mpg. But due to it's extra weight that might X out any increase in mpg..

    I have heard that if you put your arm out the window, that right there is 3 mpg loss...

  • kit1404kit1404 Posts: 128
    None of the above is likely to make enough difference in gas mileage to be worth consideration.
  • greg116greg116 Posts: 116
    You all have valid arguments when it comes to aerodynamics and such, but I've seen little discussion about simple tonneau covers! Wouldnt that provide the "gain" in economy without the wear and tear on your hinges and straps, or added weight (and price!) of a cap? Okay, they reduce cargo capacity, but most people dont have anything in their beds most of the time anyways, right? You could get a lightweight snap-on cloth/plastic thing that comes off in seconds.
  • greg116greg116 Posts: 116
    ...But if you put out your hand so the palm is facing twoards the road, and then tilt your fingers up, wouldnt that deflect air and make the vehicle lighter? j/k
  • Plus some covers roll up when you need to haul stuff.
  • greg116greg116 Posts: 116
    My father bought a '98 Durango 4x4 SLT 5.9 and (I think) 3.92 rear end. After the break-in, it saw extensive highway driving. After seeing the damage caused by all these highway miles, he put on a bug deflector. Not only did it dramatically reduce stone damage, but from what I can tell, gave us another 3MPG! I drove it on a 14-hour two-day trip over the Rocky Mountains and averaged 18.5 MPG. Okay, it was pretty well empty, and just me driving with a light foot taking my time, but I don't think easy driving can account for 3 whole MPG by itself...
  • obyoneobyone Posts: 8,054
    which leads to the methodology used to calculate the mpg. How was it done?
  • greg116greg116 Posts: 116
    Trip computer. True, they're not the most accurate things in the world, but it's been pretty consistent so far.
  • Many months ago I saw a post from some guys with access to a government wind tunnel and tested the coefficient of drag on their new Silverado with tailgate up and down. The tailgate up actually had a very small advantage but too small to make a difference. I remeber it because it seemed so odd but can not remember who posted the results.

    I have a hard tonneau cover on my '00 Z71 ext cab and noticed a small improvement (.5 mpg) but then Vegas changed to that oxygenated gas and everything went to heck.
This discussion has been closed.