Will i notice an increase in MPG's if i lower my tailgate? I do not have a covered bed and my 91 ranger has the long box...7 foot i believe. Does an "air-gate" really work or is it a waste of money?

-hooD

 

There has been much controversy on this subject.But scientific principal and theory dictate that air coming into the bed(with the tailgate up) swirrels around creating a pressure pocket,so that continuing air flow is diverted over the bed.lowering the tailgate produced no less wind resistance.(the main thing is driving around with the gate down just does'nt look very cool.) And a well placed bump or railroad track could cause you to loose it.

 

I saw a study by some kind of organization that specializes in measuring the effect of air flow on objects. Can't recall which one it was, I'm trying to find the data again, but it seemed very legit. Anyway, the study concluded that there is no advantage to dropping the tailgate, inasmuch as the bed "cup" design helps to create a "cushion" of air that essentially acts as a sort of tonneau cover and allows the oncoming air to flow over the entire truck in a smoother and more efficient manner, especially during highway driving. In fact, overall, dropping the tailgate resulted in more wind resistance and less gas mileage.

 

I've also read studies that show that lowering the tailgate does not improve mileage, and in some cases worsens it. If your owners manual is like mine (and I'm quite sure it is), it will advise against driving with the tailgate down due to the possibility of hitting a bump and having the tailgate fall off. I can only imagine what a jury would think if the lawyer for the plantiffs who suffered injury or even worse stood up in court and read those lines in that manual to the courtroom.

 

I get to go against the flow here. I have seen study's both ways. The one that stood out the most was one was by a university using a wind tunnel and it clearly showed the drag produced by the tailgate. It tested a dodge ram with tailgate up, tailgate down, tailgate removed, bedcover, topper shell, and with a specially engineered shell specifically designed to reduce drag. Tailgate down reduced drag significantly, more than with the tailgate removed. The bed cover was even better, and the engineered shell was the best. I think the topper was the worst. I usually run on the interstate with it down and notice maybe 2 mpg difference if driving 80. I am convinced that tailgate down does reduce drage therefore increasing mileage. The drag produced by the tailgate up is evident in the fall when the leaves in back are swirling all over the place. Running with it down gives the air a chance to straighten out and becaome less turbulent as it moves through the box.

 

I never checked the mileage, but down seemed better on mine. I know on my truck the air WAS hitting the tailgate. I know thif for fact, because when i added the bed liner, i was racing this s10, and i noticed in the rear view something move. The air was hitting the tailgate and goig down and then under the liner. At 90 it was pretty bad. There was also a lot of trash under it, so I am sure low pressure above it was not the answer. I did notice that at speeds it felt like i had more weight on the rear and less on the front. I used to road race it , and it felt better with it off. And yes beware, that it can fly off if you dont have the cables hooked up and in good shape. This happened to me leaving the drive.

I put the airgate on, like it, and you can tell the air is going through it, cause it gets bowed out top to bottom. I also saw less leaves built up i the front of the bed with no tailgate. And let someone through an empty soda can in the bed and listen to it rattle around.

One more benefit i saw off, was i got more airflow through the cab when the windows were down/slider open. Having no a/c witht he gate on and windows opn, it seemed that the air coming in the rear would negate the side window, and even had trash blow in the slider.

I owned my ranger for at least 8 years, so i drove it under many differant setups. I also was driving 55 miles to work 6 days a week. I prefered the air gatesetup.