Just wondering, does having the tailgate down help with gas milage on freeway driving or is this BS?..

 

Mythbusters already did a show on this issue.........tailgate up is better MPG wise.....they showed the tailgate up forms a air bubble that causes the surrounding air to flow smoothly over the truck with the tailgate down the air comes over the cab and pushes down on the bed causing more drag and a loss in MPG.

 

They have actually done that one already. BUSTED!!

They drove 2 ford f-150s next to each other and the one with the tailgate up lasted 30 more miles. It was explained that having the tailgate up creates a vortex behind the rear window which helps keep down force off the rear end thus creating less drag. I still laugh to this day at all the trucks I see with thier tailgates down trying to save gas, but actually doing the opposite. I have tried telling people I see with tailgates down, but they will argue till they are blue in the face about it, so I don't anymore.

 

Cool thanks

 

I would think having a toneau cover would cause the same drag right. What do you all think. Would that actually cause more loss with mpg also. Not that it really matters to me but I was just thinking about that.

 

Thats a good question. I would like to know the answer to that one.

Cuz i have on on my truck.

 

obviously, i dont work in aerodynamics area of boeing, but if i had to stab a guess, i would assume that have a bed cover would increase gas milage simply because the bubble would still be created, and furthermore, less drag would be created. i hope they will try and tackle this question on the next version of mythbusters. they did say that they would revisit that episode with new results, so lets wait and see!

 

Bingo. Same actually happens with a shell/cap.


Another reason NOT to run with the tailgate off is over time the bed walls flex in the wind cracking the welds to the floor. Some vehicles will start cracking welds within a year, some last 5+yrs. See alot of this locally. Even a gen2 dakota had a bed wall flapping in teh breeze.

 

when I put my soft tunno cover on I noticed better gas milage on the highway. and I still get that vortex behind the cab. cause when ever there is leaves and other stuff on my tunno and I have my back window open it will all come into the cab[:@]. and also in the winter the snow will get trapped by the back window, and you can see the vortex with the snow moving around.
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You guys are correct on the tailgate down and the bed cover. There was a site I checked a couple of years ago (wish I remembered) that used an actual wind tunnel for testing.

Tailgate down- worst aerodynamics ( the air goes over tailgate and underneath creating low pressure vacuum "drag"
Tailgate up- better (due to the rotating air "bubble")
Bed cover- best (same bubble but less drag) Keep the tonneau lightweight for obvious reasons for best results.