Mythbusters show on tailgate up vs down

[tomhole]

Mythbusters last night ran a test of tailgate up vs down vs gas milage. The tailgate up got 30 more miles out of a tank than the one down. They ran a water tunnel test and determined that the captured vortex formed by the tailgate being up actually reduced overall drag vs the tailgate down which allowed the freestream air to contact the tailgate and increased drag. Interesting results.

I may email them and ask them to test a taneu <sp> cover vs an uncovered bed. Based on their data in this show, it might be a draw or the covered bed may be worse as it prevents the formation of the captured vortex.

Tom

[jasbus]

Originally Posted by tomhole

The tailgate up got 30 more gallons out of a tank than the one down. Tom

WOW!!! I'm gonna have to leave my tailgate up from now on, looks like it actually adds gas to your tank..



It was interesting, I've always wondered about whether it did any good or not.

[tomhole]

[RitcheyRch]

This shouldnt be news to anyone as there have been numerous studies of this in Popular Mechanics and other magazine articles that have said that you are better off with the tailgate up.

[LGL002]

This has been going on for over fifty years that I recall. It just keeps coming up over and over.

Larry

[Soyboy]

Thirty miles per tank on a pickup is a pretty big deal. That would seem to be around 10% or so. Lots of folks try more difficult/expensive things and get a lot less gain.

As others of said the tailgate up or down question has been going around for year. All the tests I have ever seen agree with the results of the Mythbusters...leave it on/up if you want to achieve the best gas mileage.

Years ago I read an article about this subject, where they interviewed an engineer (I believe from Ford). In that interview the engineer said that when they design the body and do wind tunnel testing, the body is shaped to help as much as possible to keep the gas mileage up when the tailgate is up. This would seem to make perfect sense. I guess subtle changes in the shape of the roof and the back of the cab can effect the airflow thereby working with the air stream changes caused by the closed gate.

[TundrastruckDave]

Wish the Mythbusters guys had done this "test" about 2 years ago! It would've saved me some $400!! I had the tailgate down on my little Tacoma and backed into one of those HUGE concrete tube barriers at a gas station, which protect the gas pumps from being hit! Since then, I've NEVER run either my Tundra or my Tacoma with the tailgate down, "regardless" of whether I was getting better gas mileage or not! Now I know I wasn't, by leaving it down!

Oh well... at least now... I know the concrete tube barriers work!

[stewairball1973]

If you would have told me that without the explanation I would have thought you were crazy. With the explanation though, it makes perfect sense! Good info to have Tomhole and thanx for the update.

[tomhole]

This is my first pickup and I didn't know about the tailgate thing. I have an Access cover, so it didn't apply so much to me.

I also didn't know that when you open the back window, everything on top and in the bed of the truck comes inside the truck. Probably obvious to the veteran owners, but sure suprised me one morning. Heavy dew on the roof, tons of leaves in the bed. I started up, rolled down the back window, got to 35 mph and was soaked and covered with leaves. With all those goofy warnings in there about airbags and seatbelts, you'd think they would put in a note about something like that.

Tom

[thumbster]

I saw the Mythbusters episode as well. I think it makes total sense what they're claiming. I once followed a landscaping truck on the freeway with a bunch of dry leaves in the bed - I remember seeing the leaves come up the cab side and get sucked downwards towards the back of the bed as soon as they got up to the roofline of the cab. Very few leaves actually flew out of the truck bed, giving credibility to the mythbusters findings about a captured vortex. I've personally noted no real mileage difference between tailgate up or down on any truck I've ever owned. I still prefer to drive with the tailgate up for safety reasons - I get really POed when I'm following someone about to loose their crap in their truck bed and come flying at my vehicle!
Wouldn't it suck if you were rearended with the tailgate down!

[rcjunkie]

Originally Posted by thumbster

I saw the Mythbusters episode as well. I think it makes total sense what they're claiming. I once followed a landscaping truck on the freeway with a bunch of dry leaves in the bed - I remember seeing the leaves come up the cab side and get sucked downwards towards the back of the bed as soon as they got up to the roofline of the cab. Very few leaves actually flew out of the truck bed, giving credibility to the mythbusters findings about a captured vortex. I've personally noted no real mileage difference between tailgate up or down on any truck I've ever owned. I still prefer to drive with the tailgate up for safety reasons - I get really POed when I'm following someone about to loose their crap in their truck bed and come flying at my vehicle!
Wouldn't it suck if you were rearended with the tailgate down!

I have also observed fast food drink containers and plastic bags swishing around the "vortex" when following a pickup truck. When the subject of an air pocket being created behind the cab and the bed came up while reading a debate of tailgate up vs tailgate down, I remember watching items of that sort float around the back of the bed. The leaves, drink containers, and plastic bags are all great visual examples for the technically challenged trying to comprehend this penomenon; it sure helped me! I do the opposite, when I need to clear my bed of leaves, I leave the tailgate down for awhile and all the leaves seem to fy away easily.

Yes, I'd like Mythbusters to followup on the tailgate vs tonneau cover.

[helica]

I am surprised so many people didn't know this.

[rcjunkie]

Originally Posted by helica

I am surprised so many people didn't know this.

There are some people who never owned a truck to care. It's like when you first buy a car, in this case a Tundra, and then all of a sudden you notice every other Tundra on the road; you now have to know whether driving with your tailgate up or down will save gas. To this day the debate goes on, it is not common knowledge; even Myth Busters had to do a show on it.

When I started noticing that my Tundra guzzles more gas than any car I have owned (with the exception of a 2000 Nissan Xterra, horrible gas mileage for a 6 cyl., Tundra V8 get's a little better), that's the only time this tailgate up vs tailgate down issue came to my attention.

[boody]

I saw that test too. I thought it would have been better if they would have done the test with just one truck. I know the trucks were identical, but just because they're the same trucks doesn't mean the gas mileage is identical.

[student's tundra]

Yeah I have heard those test before, that's why I have always left my tailgate up. My question is about a truck I see at my school. What about if your tailgate is at a 45 degree angle, what advatage is he trying to gain . Looking for aerodynamics just looks silly to me.