Okay to leave tail gate open?

Aerodynamics. The air hits the closed tailgate and causes a rolling effect. This lets the rest of the air ride over the top of it, reducing the drag. Open the tailgate and the air flows through, then causes the roll effect under the tailgate/back of truck. This increases drag and slows the truck, reducing your mileage.

That’s a pretty crude description, but the best I can do without drawing it.

 

And don't get me started on the tonneau cover on/off debate....

 

As an aeronautical engineer, that is a pretty good description of how drag is affected by rolling air or disrupted flow. But, I sure would like to see data showing the better gas mileage with the tailgate up. Not saying it's not true, airflow is a funny thing. But there is a lot of low pressure area behind the tailgate even with a smooth airflow over the top of it. Interesting.

Beary

 

mythbusters did a show on it years ago and closed yielded the best mpg results

 

Mythbusters proved that driving with the tailgate down increased drag and reduced mpg.

 

I have never seen much difference n mpg with a tailgate up or down. I have seen rock chips from having it open.

 

Thanks

 

OSU, class of 82.

Beary

 

Go Pokes 07 here

 

This. Forever debunked since way back when.

 

03 Here. Go freaking Pokes

 

Mythbusters also found that you could get the best mileage by removing the tailgate and replacing it with one of those mesh things. I am kind of skeptical of their methodology. Their test was based on, like, one run per configuration.

However, I definitely agree with the broader consensus that tailgate up is better than tailgate down for mpg. Iirc mythbusters aren't the only ones who reached that conclusion.

 

What about the tonneau cover mileage.

 

Not sure I want to leave my TG down unless I was hauling something. I would be afraid some A-hole would hit it but even up getting hit in the back (even lightly) causes damage especially since the 3 gen has such great rear bumpers! Usually, if I'm hauling something long I just use my 6' x 12' trailer.

 

This is a smart man

 

Beary, there are a couple of other interesting things on the Tacos. The top of the tailgate is shaped similar to a spoiler. It is shaped this way to reduce drag. Look at your taillights. Look at the bottom of your side view mirrors. See the little fins? Those were incorporated to add some stability, and decrease drag. There are some pretty cool videos with Mike Sweers about the 3rd gen features. Some of the videos he goes into the aerodynamics a little bit.