I watch this show on Discovery ch. called MYTH BUSTERS, they did a test to on TRUCKS to see if you really get BETTER MPG driving with the tailgate down vs driving with it up. For the test they got 2 of the SAME trucks with BONE DRY fuel tanks and added the same amount of gas in both. Then the RULE was they could ONLY take off useing their cruse making sure one did not step on the gas more then the other when taking off from a full stop. MUCH to everyone's suprise the truck with the gate DOWN ran out of gas first, the other truck went on for another 30miles !!! I WAS SHOCKED......... so were the guys on the show. Now they did another test to see WHY and WHAT made it so much better to drive with the tailgate UP. So they got a die-cast model of a truck and put it in a big fish tank full of water and at one end of the tank they dropped in a SMALL moter with a prop, acting as wind..... and useing some oats they dropped them into the tank. The truck had its gate up and as they dropped in some oats they begain to gather in the back of the truck, BUT they STARTED to make a swirling motion near the back window of the truck. NOW this swirl was acting like a ramp for oncomming wind and making it so when the wind came off of the cab it would hit this swirl at the back window and go right out of the back of the truck. NOW as they were doing this test he put his hand in the tank and DROPPED the tailgate, and the SWIRL stopped and made the oats as they came off the cab go right down onto the rear of the bed of the truck at the rear window. The oats gathered at the back window as wind would do PUSHING the rear of the truck DOWN causing DRAG... !!! So for those tho dont have a bed liner it IS better to drive with your gate UP then down. INTERESTING!!!

 

http://www.findarticles.com/p/articl...39015#continue

 

yeah, somebody posted a link in the "Sights & Sounds" forum which had the video of the water tank test. Pretty interesting stuff. Maybe those guys who put their tailgates down at the track are actually hurting their times. The mythbuster guys were saying that with the tailgate down, the wind actually pushes down into the bed of the truck, rather than bouncing off.

 

Believe it or not this has been a known fact for many, many years, I've known this since I was about 12. People just think that having a big piece of metal, like a tailgate sticking up hurts airflow, when really it's the opposite.

 

I can't understand why people can't understand that automakers spend MILLIONS, if not more, on R&D to get the smoothest, most efficient vehicle stock that they can before a vehicle is released. Somehow, I think they probably took the whole tailgate thing into condideration already. I mean, if it took something as simple as dropping the tailgate to add that much MPG, then I think their R&D techs would be fired pretty quickly!

 

what's a bedliner have to do with anything?

 

I ment ANYONE with a bed liner this really wouldnt affect if their tailgate was up OR down, it pertty much ONLY applyed to those without one. Those with a bed liner are NOT going to get any wind drag with a liner on their truck bed.

 

you mean like a tonneau top or camper top? maybe I'm a tard, but I can't fathom how a bedliner would make a difference at all...

 

OOPS, no im the tard........ I ment bed COVER. sorry

 

Yeah, my dad has a fiberglass tonneau cover. It looks really good and he gets better mileage.