Soft Tonneau Cover = Worse MPG?

[RB43TD]

Is it possible that a soft tonneau cover can actually make MPG worse? I bought my new 22 Rebel in early December. It's the 5.7 HEMI gas, no e-torque. No tonneau cover to start. I was lucky to get an average of 15 mpg at first but I expected that since it's brand new and is still going through the break in period (I have about 4K miles now). I live in Kansas City so while there are some hills, it's not even close to mountain driving or anything like that. About a month ago I put on a soft tonneau cover and since then I've actually seen my MPG go down to about 13. Same type of driving and various weather conditions with the cover and without so for the most part it's all been equal. I should also mention that I try to milk the gas as much as possible so it's just normal driving and not giving it a ton of gas to get up to speed at any point.

This is my first truck so just wasn't sure if this was normal. Every thing I read said having a tonneau cover should actually help boost MPG a little bit but I'm seeing the opposite. I have noticed that the cover shakes a lot (makes sense since it's soft) but i have it as tight as I can get it. Didn't know if that constant shaking/vibrations could be causing issues as well.

I didn't buy the truck for the MPG. Definitely get that. I was just curious if anyone else had experienced this.

 

[zogg]

Tonneau cover should not cause any decrease

Some years ago, a university did a test with two identical F150s…one with a tonneau and one without. They drove them from New York City to Chicago and the truck without the cover got a very minimal better mpg. Something like .05 mpg.

 

[andymax]

That has not been my experience...I get the same or slightly better with the my Extang Trifecta Soft Trifold. It does shake a bit at highway speeds.

 

[retired]

I think mythbusters did an episode and found that a cover did give a very minimal better mpg.

 

[Aircooledpurist]

Tonneau definitely will improve aerodynamics. Im having a Bakflip X4S installed on Thursday. Nice for bed security. It can't hurt the gas milage but I don't expect it to pay for itself.

 

[dhay13]

Tonneau cover should give slightly better MPG but not enough to notice. I'd bet a windy day would make a bigger difference over a day with no wind

 

[RB43TD]

So, just an update. I'm through a half tank since I rolled up the cover and I'm at 15.2 mpg average. I haven't been averaging that much since I put the soft cover on a month ago. I will see how the rest of the tank goes. When this tank is empty I will refill it and then drive that whole tank with cover down.

 

[Rlaf75]

From my observation, these truck get anywhere from 12 to 15 mpg based off of just the posts I see regarding gas mileage. These are heavy trucks with a V8 engine and arent known for their fuel efficiency. I'd suggest doing your own experiment and drive it with the cover off for a few tanks then with it on for a few tanks and comparing the mileage. There are a lot alof variables that affect the mileage such as idle time at traffic lights, weather and road conditions. I wouldn't lose sleep over it

 

[retired]

yup to many variables unless doing some very long term controlled tests.