Mythbusters testing tail gate myth

[Michael Lighthall]

Mythbusters are testing the myth of the tail gate up or down right now on discovery. I know we talked about it before here. In case anyone cares.



Mike

 

[ChrisW Vincent]

I am watching as well. Can't wait to see the results

 

[Travis Munday]

The tailgate down ran out of gas first.

 

[ChrisW Vincent]

Geeze I would have never guessed that one! Weird

 

[scott r]

It could be any number of factors, why the truck with the tailgate ran out of gas first though.

I do find that I get a little bit better gas mileage with the tonneau cover OFF of my truck, but I think that's more of a weight rather than an aerodynamic issue.

 

[shawn stonbraker 2]

Good data on that one. Made alot of sence seeing it done in the water with the oatmeal. Just wondering what the difference is with a tonneau cover on. That "vortex" would be missing on it also, right?

 

[scott r]

Ok, what the hell are they thinking? Sticking your finger in the end of a gun is not only DUMB, there's NO WAY it could work! Some of these myths are just ignorant.

 

[Thomas Rogers]

The tailgate down ran out of gas first.

Over a million rednecks are wrong???? What's the odds!

 

[Brandon Hughes]

Unable to watch. How did the tailgate down run out of gas first?

 

[Michael Lighthall]

I was shocked to see the shotgun balloon a little on the one test. That was pretty good. But shoving the barrel into the ground and plugging it with dirt, I can't wait to see that.

 

[scott r]

For those of you who missed it and have access to a TV, it does come on again in 3 hours, at midnight Central Time. If there are people who don't have access, I could probably capture it on the computer and upload it to my website, let me know if you want it Brandon and I'll get it for ya.



-Scott

 

[Boodrodon Dykes]

Just a thought, I'm not too great on auto sciences, but for a quick thought could it be because the one with the tailgate down won, is because the weight of the tailgate down goes further back on the truck so that means more wieght on the back tires. So then the tires have to push harder to rotate, thus using more gas. Im probably wrong , but only thing I am capable of thinking of.





boodro :unsure:

 

[Travis Munday]

Um...no Boodro. It all has to do with aerodynamics. The tailgate creates a 'bubble' of air, keeping air from flowing over the rear of the truck. With the tailgate down, there is no bubble and the air travels the entire length of the truck and contacts more hard surfaces, that means more aero drag, which means lower gas mileage.



Hyuz-

There were two identical trucks (Frod 150's at that), with the same tire pressures, very similar mileage, identical options, etc. The only difference was one truck had the tailgate up, one had the tailgate down. Being the test was done over real roads by real drivers, the results are a little more realistic then lab tests. BTW, the truck with the tailgate UP went 30 miles further down the road the the truck with the tailgate DOWN. Not a huge difference, but enough to make it to a gas station in almost any situation.

 

[scott r]

That's a very interesting result. I have heard for YEARS that tailgate DOWN was the way to go if you wanted better gas mileage. I missed it earlier, but I'll be watching in 1 hour and 48 minutes when it comes back on.

 

[Richard L]

I would be curious if they would have gotten the same results if they used a standard cab truck and not a 4 door crew cab? I think the air flowing over that long roof may help create that buble of air in the bed, where a shorter cab may not have that same effect.



Anyway, I think that is why the earlier comparisons of the Sport Trac with and without the tonneau cover does not noticable effect the gas mileage.



...Rich

 

[Ben Poche]

they should do the test 2 times switching trucks,no vehicle is created equal

 

[John Salov]

okay heres my thought, even though u read the thing University of Michigan put out.

Hold a loose leaf sheet of paper under ur lip and blow. its lifts up. maybe it has something to do with that too? and the bubble effect is lost.

 

[TomT]

All those rednecks that have been driving with their tailgates down all these years are going to have to go out and get the Tornado Fuel Saver now.

 

[Johnny O]

I don't discount the bubble effect, but my first truck was a vastly underpowered '99 Ranger Supercab 4x4, 3.0/stick/3.73 gears. After I put a tonneau on, it held speed on the highway noticeably better.

 

[Keith McElroy]

I think the test needed to have three trucks:

1. tailgate up

2. tailgate down

3. tonneau cover



It would also depend on the temperature of the air, as air mass/density would affect the magnitude of the drag.