Tailgate Up for Better Mileage

Recent testing by GM of the truck bed regarding air flow, revealed an interesting piece of data that could stop truck arguments cold.

According to their aerodynamic engineer, leaving the tailgate up is more efficient than leaving it in a lowered position.

It seems that with the tailgate up, the air flowing over the cab falls downward against the back of the cab, pushing the truck forward. With the tailgate lowered that air escapes and doesn’t add any benefit.

They also advised against nets covering the back of the truck.


Replacing the tailgate with an aftermarket net is worse than having no tailgate at all . . . According to their engineers it is equal to a boat dragging a solid object and fishing net through water, the net is going to require more muscle.

http://truckingtimes.com/articles/pickup-truck-tailgate-up-or-down-aerodynamics-tested

 

Mythbusters covered this topic twice and said the same thing.


http://www.youtube.com/watch?v=r3aqHbD-O9E

I guess +1 to GM for confirming?

 

I tried to watch the video, but got this message . . .'This video contains content from Discovery Communications, who has blocked it in your country on copyright grounds.'

Even not seeing it, I guess the evidence does lean towards leaving the tailgate up.

 

Sorry man, this is nothing new... Tailgate up for better MPG has been tested and confirmed many, many times. Tailgate down makes the bed and tailgate act like a 'wing' similar to the whale tail wings on drag racing cars. This creates downforce and drag, hurting your fuel economy.

 

The testing was done on the 2014 Sierra models and this was based on GM's findings. But the studies were a little more in depth than previous studies.

The Sierra spent more development time in a wind tunnel than any GMC pickup for achieving better fuel economy.

Tonneau covers for the bed help smooth airflow over the truck, soft covers are more beneficial than hard covers because they form to how the air wants to flow.

Running boards can also help air flow smoothly down the truck’s sides.

Round, tube-style running boards can provide a minor improvement to the truck’s drag coefficient, while “Fully integrated, flush-mount running boards are even better.”

http://media.gm.com/content/media/us/en/gm/news.detail.html/content/Pages/news/us/en/2013/May/0516-gmc-pickup-aero.html

 

Great . . . I add a hard cover for security and find out the soft cover is better for airflow.

Perhaps one of the manufacturers can come up with a hard cover with a softer pliable shell. Then again if they did, would the difference in cost be worth the added gain in mpg?