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Old 03-13-2008, 03:33 PM   #21 (permalink)
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I always thought the this was wrong. Tailgate down should be more fuel efficient. I always thought that the tailgate up would act as a big flat panel stopping the air stream. so tailgate down would lessen that drag.

I have learning a lot about aero in the past couple of months in this forum. Most of the drag in the rear of the car comes from back pressure. The more flat surfaces that are perpenducular to the airstream create low pressure areas and thus create drag.

The pickup bed up gives one step at about the correct angle for limiting the drag. With the tailgate down you get the full effect of the entire flat surface of the back of the cab. This creates a large low pressure area. The tailgate up lessens this some.

Thus tailgate up should be better.

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Old 07-13-2008, 03:16 AM   #22 (permalink)
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ok... so what about a tonneau cover or a mesh net? worth it or not? I was planning on buying a mesh then later on doing some cheap tonneau cover thaqts light!
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Old 07-14-2008, 01:35 AM   #23 (permalink)
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I'd think that not all trucks are created equal for a generalization to say one thing works and one thing doesn't..

funny that street bumped this, I was thinking about this earlier today..
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Old 07-14-2008, 02:00 AM   #24 (permalink)
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Quote:
Originally Posted by Street View Post
ok... so what about a tonneau cover or a mesh net? worth it or not? I was planning on buying a mesh then later on doing some cheap tonneau cover thaqts light!
Done:

OPEN:


TANO COVER:


FASTBACK:


Using the flow illustraightor, and my '69 CST10 as the truck
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Lets see how far it can go

"All I know about music is that not many people ever really hear it. [...] But the man who creates the music is hearing something else, is dealing with the roar rising from the void and imposing order on it as it hits the air. What is evoked in him, then, is of another order, more terrible because it has no words, and triumphant, too, for the same reason. And his triumph, when he triumphs, is ours." -Sonny's Blues
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Old 07-14-2008, 09:43 AM   #25 (permalink)
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Interesting. It looks like a fastback cover would be even more effective if you removed the tailgate and brought the back end all the way down to the bed.

Such a cover would be great for people who have a pickup just for occasional towing.

Back when I had a truck, the tailgate was very heavy. I'd guess 100+ lbs.
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Old 07-14-2008, 01:36 PM   #26 (permalink)
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Originally Posted by jonr View Post
Interesting. It looks like a fastback cover would be even more effective if you removed the tailgate and brought the back end all the way down to the bed.

Such a cover would be great for people who have a pickup just for occasional towing.

Back when I had a truck, the tailgate was very heavy. I'd guess 100+ lbs.
What truck? I would guesstimate the thick steel one on my '69 CST10 is 75ish pounds. Don't think newer tail gates weigh that much.
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"All I know about music is that not many people ever really hear it. [...] But the man who creates the music is hearing something else, is dealing with the roar rising from the void and imposing order on it as it hits the air. What is evoked in him, then, is of another order, more terrible because it has no words, and triumphant, too, for the same reason. And his triumph, when he triumphs, is ours." -Sonny's Blues
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Old 07-14-2008, 02:14 PM   #27 (permalink)
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personally, i think driving with your tailgate down should be illegal unless you are hauling a load. take a look at how tailgates attach. one side in a pocket, the other slides into its "pocket" at either a 45 deg angle, or past 90 (depending on make/model). all the bumping from the tailgate down and bouncing around can stress the cables to the point they break. there goes the tailgate past 90 degrees, and into someones windshield.

awhile back, i was curious as to how dealerships were having so many tailgates stolen off new trucks. so i decided to see how easy it was to remove the tailgate off my (now sold) truck. found out i can take a tailgate off in less than 5 seconds. they are not held on as well as you think....

and don't get me started on people that drive tailgate down with a bunch of crap in the back (spare tire, gas can, scraps of wood....)

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