Tonneau cover MPG gains

Purely going off of the computer but it seems to be accurate from what others are posting. It's week 1 so I'll have more info as I finish the tank.

 

my bad should have specified. All four windows up. Only the back one open to allow air flow from the vents through the cabin and out the back

 

Not to burst your bubble, but so have I since the weather has warmed up. I run the tonneau cover all winter unless I need to haul something. I've been getting 15-18 depending on the temp outside. The last couple days my mileage has varied from 19-22. All of that at 70 MPH for about 45 miles each trip.

I do see you have a 2021 model too. Not sure how many miles are on it, but break in period plays a pretty big factor too.

 

Ah. Interesting. I’d be surprised if it would even net 0.5 doing that. But if you consistently run air through your truck and then give it a chance to come out and add to the stuff coming down off the roof and around the sides, maybe that makes a difference. Only one way to do it proper:

 

I noticed something similar on my truck with a different situation and thought of this comment. At 70 MPH, if I open the sunroof fully and the rear slider, then open the front windows about 1" and the rear about 2" I also seem to get 1-2 MPG gain pretty consistently. No tonneau though.

 

Idk about mileage gains with a tonneau cover, except my truck performs noticeably better than a buddies 2019 double door cab trd without the tonneau cover. Could be other factors, but both are now stock trucks.

 

But the 25 HP gain from the Tonneau Cover should help my fuel mileage, right?????

 

Only if the truck has monster stickers plastered on it.

 

I'm now at 56k and commute often. I average 22MPG

 

Nice! What speeds do you run?


I got this anomaly yesterday, but I also didn't go over 54 MPH due to ice, and mostly slower.



I got this one the other day "drafting" a semi at 70 MPH.

Neither is typical for me. At least this time of year. But, then again, I'm usually running about 70 MPH.

Edit: I see you're in SoCal so that makes a big difference too. I will get much better in the summer. 21-24 can be typical on the same commute. But I also don't regularly run the tonneau cover in the summer.

 

Ive noticed My MPGs have improved as well with my tonneau cover. Its really noticeable on the Interstate. The tailgate acts like a parachute.

 

Myth. No different than driving with the tailgate down. In fact, an empty bed causes initial airflow to swirl and develop a "bubble". Then all subsequent airflow rides the top of the bubble without contact to the bed, tailgate, tonneau or whatever. Therefore causing less air drag.

 

Nope. I have a BakFlip cover, no MPG gains or loss.
But it looks good!

 

things I have noticed in driving toyota truck since they were called minitrucks.
Winter vs summer gas makes a big difference
cruise control on vs off makes a difference if there are hills
How fast you drive
What elevation above sea level you are driving at
In the picture I was down at 3,700 feet above sea level. I live at 5,200
windy road 45 speed limit no cruise control on
lots of different factors but for me its speed and elevation

 

Not entirely true. I used to believe this, but they're two different things. Slightly different, but different.

The Myth busters tested this and found similar results to the 2011 study by the US Department of Energy. The hard tonneau cover was about 3.6% more efficient while the tailgate down was less efficient than normal driving. The difference is negligible, but still there. The tailgate down is lower and longer than a tonneau cover and forces the air down harder on the back of the tailgate, causing more drag.

That was also done back in the days where little thought was put into aerodynamics and fuel efficiency of trucks. Today you'll see a lot of other aerodynamic features on trucks, such as the little fins on the Tacoma, the hood designs to affect air flow, the spoilers on the back of cabs, and the lips on modern tailgates.

 

I have the idea of placing a board with the width of the bed at a 45 degree angle against the tailgate would improve the gas mileage. I always wanted to try it, but never have the time. Do you think it would improve the gas mileage? Readers with aerodynamic expertise, please chime in. Thx

 

Haha yup, i bought mine to keep the weather out while the gear is in there and keep it secure while traveling.

iirc the best mpg gains is had from a mesh tailgate and an empty bed