MUST READ!!!!!!!!I received my summit racing catalog, and found an interesting article about gas mileage. They have recently proved that PUTTING YOUR TAILGATE DOWN worsens gas mileage than just leaving it up. When the tailgate is up, there is a sac of air inside the bed that bounces some air back up. When the tailgate is down, however, the wind flows from the top of the cab straight down to the bottom of the bed. I'm no aerodynamics expert, but from what I read, I believe them now.

 

I've heard this befor also. However, I've also heard the other way! I guess it's up to the myth-busters!!
P.S. I just always leave mine up...if someone rear ends you with the gate down, they can get out of it and make you pay (so Iv'e heard...another case for the myth-busters??!)

 

They already proven it, the tailgate down is worse. They've also tried no tailgate, a tailgate net, and bed cover.

 

What was the outcome with a topper or cover, better or worse?

 

Mythbusters has had two episodes on this,
the 1st time they did a long highway test with two identical Ford F150s running in convoy on an interstate, one with the tailgate up and one with tailgate down, until one truck ran out of gas. The tailgate up got the better MPG, but by less than 1.

The 2nd time they tested it was with a motor boat fuel flow gauge (Flowscan company) retro-fitted to a Dodge Dakota regular cab. Adam claimed he had spent considerable time 'calibrating' the Flowscan gauge.

The 2nd tests were short on a crowded California highway at 25 and 55 mph, and they tried to read the Flowscan meter by eye to find the MPG, even though the Flowscan will only read to a tenth so that the best they could do was notice differences of about 2% (0.1/5.1 gallons per hour). They did travel up and back that stretch of highway to try to cancel out head and tail winds, but could not cancel out side wind effects. These results with the Dakota & Flowscan meter by Mythbusters reported that tonneau cover and tailgate up were better than either tailgate down or tailgate off. Adam's most controversial finding with his Dakota in this 2nd set of tests was that a plastic net with about 1 inch holes in place of the tailgate seemed to be best of all....but only slightly.

After reporting these results, the Mythbusters said they were
'totally sick of doing MPG tests with pickups'
and did not want to get any more emails or letters on the subject.

You can watch any of the Mythbusters past episodes by downloading files at:

http://www2.digitaldistractions.org:8080/torrents.php?showid=mb

 

Yup, my uncle told me that back in 2001. Gotta go!