Tailgate up or Tailgate down???

[ComancheKid45]

Ive been meaning 2 post this many times but just forgot, anyway has anyone tried testing fuel milage with the tailgate up or down, and if so did it or would it make much of a difference.....ive heard mixed reactions on pickup tailgates but since i drive a Comanche i figured i only wanna know about the Comanche 8)

[comanchedude]

Possibly be worse with it down

Normally a "bubble" of air is developed in the bed while driving and has no drag on the truck, if you lower the tailgate there will be no bubble and your tailgate can act as a spoiler and produce drag “ie cost mileage” but more than likely not very mesurable

 

You should run gate up as designed by the engineers, also this has been tested and proven. It’s not my idea or theory it is a technical fact.

[mj_lover]

i disagree mate, tailgate down, it was designed to hold stuff in the box, not to help with aerodynamics (sp?) using high tech engineering software (ms paint) i shall show air flow.

 

 

blue is with tailgate, red without.

 

them caps or tonnue (sp?) covers work well. too, keeps the majority of the airflow out of the box, which reduces swirling.

[pingpong]

Problem with gate down, is stuff can fly out of your bed. Also it could get damaged. tail gate up... welll I do believe the drag caused by this is very small, that it would take some long term testing to figure out which is better.

[jeepmj_tj]

Possibly be worse with it down

Normally a "bubble" of air is developed in the bed while driving and has no drag on the truck, if you lower the tailgate there will be no bubble and your tailgate can act as a spoiler and produce drag “ie cost mileage” but more than likely not very mesurable

 

You should run gate up as designed by the engineers, also this has been tested and proven. It’s not my idea or theory it is a technical fact.

 

I agree with C-dude. Once you get rolling, an air pocket will for inside the bed and all remaining airflow will pass over in a streamlinded fashion. With the tailgate down the airpocket will not form and the resultant airflow will apply downforce to the back of the pickup causing drag.

 

Mythbusters tested this as well. Not that they are always correct, but i believe them on this one.

[whowey]

MJ-lover---> Your airflow diagram is incorrect.

 

I used state of the art technology(a big pile of oak leaves). and opened the sliding rear glass. Going down the road, leaves were whirling around and flying in the open Rear window.

[mj_lover]

it is possible that i am wrong, could you draw a picture? i think i know what your saying, but would like to be sure, thanks

[Stumpy]

i kinda tested this when i had my hemi and it really didn't make enuf of a difference, except that my tailgate would bang up and down makin all kinds of noise. i always left it up because i was worried about damaging the tailgate from it slamming around.

[87manche]

mythbusters tested this with two f-150s.

Tailgate down was a noticeable decrease in mileage.

[Pete M]

I wasn't entirely satisfied with the Mythbusters' expirements (they left waaay too many variables unaccounted for). Check out:

http://www.roadandtrack.com/article.asp ... le_id=1455

http://community.discovery.com/groupee/ ... 948218/p/1

Jeep on!

--Pete

[87manche]

it certainly wasn't the most scientific experiment, but it was good enough for me. Besides I figure tat it wouldn't be all that noticeable with the tailgate down. I'd rather leave it up, so it doesn't get broken, or rattle. I HATE rattles when I'm driving, I finally tracked down my high-speed rattle, and can say that my MJ is as quiet as she can be when going down the road considering what she is. At least it doesn't have any more rattles and creaks.