Ilovemountains

Hi guy I have an age old question and hopefully some one will know if there is any truth to it. Does driving with the tailgate down on a pick up give you better gas mileage? I had read that keeping it up creates a spiral effect in the bed and that it is better for fuel economy to leave it up, then I read that if you leave it down on the highway you will get better miles because you are taking away the parachute effect from the rear end. I am just curious, I have a long road trip coming up and I may run 100 miles up and 100 miles down all on I81 at 75mph just to see if there is any difference. What do you think??

PoBoy

It's a myth and actually yeilds worse gas mileage driving with it down. There are various studies out lately proving so...

http://www.fordf150.net/howto/fueleconomy.php

Nathan Buchanan

I don't know if you've ever listened to "CartTalk" on NPR (there are two brothers that have been mechanics forever; the show is pretty fun to listen to), but I heard someone call and ask them the question. They researched it and said there was no truth to it; driving with your tailgate down doesn't increase your gas mileage. They said what driving with the tailgate down does do, however, is make the bed of the pickup less safe in an accident. With the tailgate down the pickup bed loses some of its rigidity, and by getting rear-ended with the gate down, the vehicle and the driver could suffer worse damage than if it was kept up.
I've tried driving with mine up and down, and I have the exact same mileage either way, both on my Toyota pickup and an old Chevrolet I used to have. I figure leaving it up and possibly being better protected in a collision is a pretty good idea.
-Nathan Buchanan

PoBoy

Here is a somewhat technically answer...myth

http://truck-bed-covers.com/Tonneau_..._save_fuel.htm

amusement

My experience from driving hundres of thousands of miles on I5 between PDX and SAC (95-04) is tailgate down offers a small MPG increase (about 1 MPG) based on a 3.0 4x4 extra-cab 5 speed. In my Taco, 4cyl exta-cab 5speed 4x2, it didn't make any difference.

The spiral effect, here named vortex, keeps the rear stable (tail gate up) during moderate cross windws. The vortex affect is a love hate relationship with me. I know it causes a down draft against the tail gate but, enjoy the stability during cross winds.

My last comment is about .... non-attentive dirvers. A tailgate down is an open invention for a poor driver to either cross lanes and hit you or just run into the tail gate from behind.

Those are my thoughts. Oh, I don't use tail gate nets. Never had a need, or was it, a pickup isn't a pickup unless it has a tail gate and a rear bumper.

Peace

obxfishn

I will disagree with that. The tailgate acts as a parachute if you will, and the air coming up and over the cab of your truck hits the bed and then the tailgate creating a drag. You will definitely increase your gas mileage with it down.

96LtdYota

I have the easiest cure....
























GET A 4RUNNER!!!!! no bed = no drag. Bam, I win again....

Ilovemountains

That a good one!!!!
+

PoBoy

"According to design experts, the truck tailgate if designed to create a cushion of air in the bed that aerodynamic engineers called a "seperated bubble" (the real nerdy ones refer to it as "Locked Vortex Flow.") Jargon aside, this invisible bubble of air actually helps deflect the faster moving wind coming over the cab so it passes over

the truck's raised tailgate, keeping drag behind the truck minimized.

"Putting the tailgate in the down position tends to increase turbulence and drag of the open box," explained Jack Williams, of Ford Aero Systems Engineering. "We've seen drag increase as much as .5 to 1 percent. Flow-through, web-like fabric replacement tailgates tend to increase drag even more; we've seen increases as much as 4 to 5 percent." In a nutshell, all of that extra drag translates into worse fuel economy for the vehicle.

Dr. Edward Fitzgerald, an aerodynamics expert and a jet engine designer with Boeing, added that the effect is actually magnified with speed increases, so that 1 percent increase in drag with the tailgate down as city speeds has much more adverse effects on fuel economy at 70-75 mph on the open road.

Contrary to another5 popular myth, pickup size doesn't matter. Toyota engineers report that although the haven't done any EPA testing, they speculate dropping the tailgate can actually decrease fuel economy depending on the cab and bed configuration of the pickup.

"

Waterboy

Same here, my truck would consistantly get 1 mpg better with it down. I just had to deal with people telling me it looked stupid all the time.

superjoe83

not necessarily, runners have a little more weight to haul around than a pickup, so that equates to more gas being used