Tonneau Covers and Fuel mileage

[NickBomb]

No they don't improve mileage. Have had my tri-fold tonneau cover for 5 years now. Have yet to see any improvement in fuel mileage. HOWEVER they are great to have. If you are only looking at them in the form of gas savings, it's a waste of money. If you want something that will protect your cargo (as long as it fits under the cover) then they are well worth the money.

 

[gixxer]

I didn't notice anything, nothing that wasn't negligible or couldn't be explained by a dozen other factors. The way they design the trucks and how desperately they are after fuel mileage. If it was worth it, they would do it and pass the cost onto the consumer.

It's more about keeping things hidden and from getting the elements on stuff.

 

[theamazingkuskus]

I'm sure it helps a bit, but I have a 2.5 inch lift and larger tires and I don't think it made a difference. Also depends on what type of driving you do - I'm sure with mostly country driving it would have more of an impact.

 

[Alweeja]

No it will not improve the mileage, if they did it would be factory. Good for storage but not for improving mileage.

 

[corneileous]

I think it all primarily depends on how you drive and how long your bed is. Maybe it doesn’t matter as much on a pickup but at least when it comes to my 30-foot end-dump my boss bought me with a rollover tarp, I started noticing about a mile and a half to a two mile increase in fuel economy compared to pulling our older end-dumps that had the regular screen tarps that were always open when empty.

We don’t run with the tarps closed when empty on the new trailers because of that, it’s more because of the design of the tarp and that in order for the plastic liner to expand and shrink, it can’t just be secured down like you were screwing a piece of plywood to a floor or a roof. Because of that, the vacuum created other the trailer supposedly sucks the liner loose causing it to become unattached and come out with the load....lol. So re have to run tarped even empty and we get a little better mileage to boot.

But as it’s been said several times, no one really buys a tonneau cover for mileage.


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[NikNak]

I just added a SnugTop topper & am heading out for an 3hr highway drive. Brochure claimed 10% mileage savings. I’m just glad the cases of ammo will stay dry. I got 22.5mpg with a full bed of camping gear & no topper in June. This is CA & they switch to “winter fuel” mix in Oct so I’m not sure it’s a true test.

 

[rvance]

In my experience, no.

 

[2019RamInSC]

New guy here. My experience and opinion, yes it does. Especially at higher speeds.

I used to have a 1995 Dakota 4X4 with the 318 motor.

With tailgate on the top speed was 102 mph. With tailgate off it went to 107 mph. 107 as I recall was also the limit set by the ECU. So possibly it may have gone faster.

All about wind resistance. Simple physics

Have fun!

 

[TomB 1269]

Interesting, there was an article years ago done with a Ram that had a V10 I think and its top speed. The long and short was that no cover was slower than a covered bed, and that a tonneau cover was faster than a cap. There explanation for this was actually weight difference. The only thing that was not clear was hard vs soft tonneau. I would agree that most of us will never see any real difference other than protection for our stuff, mainly due to the fact that to truly see the effects, long term sustained high speeds are required. I equate it to the A/C vs No A/C test that Mythbusters did, in which windows up and A/C on actually resulted in sightly further distance for the same amount of fuel on a speedway track due to the decreased drag. It is clear that an open bed with tailgate will generate more drag then a covered bed. The issue I always had with the mythbusters test was that they utilized a constant 55 mph speed, which due to the air turbulence causing a bubble effect in the bed would possibly be more efficient at 55 mph, as it may act as a dome over the bed in line with the cab roof, vs a tailgate down or tailgate net. However, the higher your speed the more the turbulence the larger the bubble and now it starts to impede the air flowing over the top of the cab and may act more like having a large box that sticks above the cab roof in the bed.

Check out the GM article on the 2014 Sierra;
https://media.gmc.com/media/us/en/g...news/us/en/2013/May/0516-gmc-pickup-aero.html
Particularly the bottom of the article;
"So what accessories can truck owners add to help aerodynamics? Tonneau covers for the bed help smooth airflow over the truck, and Bloch says 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,” said Bloch, “Fully integrated, flush-mount running boards are even better.”"

 

[2019RamInSC]

Check out the GM article on the 2014 Sierra;
https://media.gmc.com/media/us/en/g...news/us/en/2013/May/0516-gmc-pickup-aero.html
”"

Good article. Found this interesting in that article:

“We discovered that in the computational analysis we perform,” said Bloch. “The most harmful air between the cab and bed was coming over the cab and down through the gap, so we paid the most attention to that specific area.”

So that little gap between the cab and bed wreaks more havoc than I would imagine.......Hmmm Bring out the duct tape

Of course based on my findings. How do I explain this:

"A long-disputed topic among truck owners is whether a tailgate raised or lowered is better for aerodynamics, but Bloch says a tailgate in the up position is more aerodynamically efficient. As air flows over the truck, it falls over the cab and pushes forward on the rear of the truck. With the tailgate down, the benefits of that airflow are diminished."

Hmmmmm

 

[turkeybird56]

All sorts of opinions and "facts". I have one on MY 19. It did improve the mpg a tad, but not really measurable, maybe .5 mpg better. Does help a lil with aerodynamics in a bad wind, but the main purpose would be keeping things/stuff in bed dry, especially since I have the full fiberglass cover. BUT, IF U buy a Hemi, why R U concerned with MPG?????? LOL. I do get 13-18 mpg in town and up to 22 mpg and a lil on hwy, hand calculated, but here is the reality:

If U wanna drive yer vehicle, regardless, unless U got an all electric, U gonna have to buy fuel, LOL...But then I's just a Boird... ALL IMHO....

 

[Donald Parker]

I have a BakFlip G2 and did a direct comparison before and after on my 1 hour commute and found just over 1 mpg improvement. Plus all of the other benefits of secure cargo storage and keeping out the elements.

 

[corneileous]

All sorts of opinions and "facts". I have one on MY 19. It did improve the mpg a tad, but not really measurable, maybe .5 mpg better. Does help a lil with aerodynamics in a bad wind, but the main purpose would be keeping things/stuff in bed dry, especially since I have the full fiberglass cover. BUT, IF U buy a Hemi, why R U concerned with MPG?????? LOL. I do get 13-18 mpg in town and up to 22 mpg and a lil on hwy, hand calculated, but here is the reality:

If U wanna drive yer vehicle, regardless, unless U got an all electric, U gonna have to buy fuel, LOL...But then I's just a Boird... ALL IMHO....


View attachment 188145

I really can’t even offer any viable info regarding whether it helps my pickup or not like I could with my big ole rock truck because in less than a month of buying my truck brand new is when I put the cover on. And then a month later is when I put them gas-hawggin’ BFG A/G’s on there which really ate up my mileage. Lol.

But at least I can say that out on the open highway I can see mid 18’s display-calculated. Not sure how much the cover and the Michelin Defenders contribute to that. I do have a pedal commander, Carven Progressive exhaust and 3:92 rearends.


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[kurek]

No it will not improve the mileage, if they did it would be factory. Good for storage but not for improving mileage.

But it is factory, on the HFE truck specifically.

 

[corneileous]

But it is factory, on the HFE truck specifically.

Yeah, but that’s only that truck which is only offered as a 2WD with 3:21 rearend, the smaller gas tank and the V-6 E-torque motor. There’s a whole lot more going on with that truck than just a factory-equipped tonneau cover.

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[kurek]

Yeah, but that’s only that truck which is only offered as a 2WD with 3:21 rearend, the smaller gas tank and the V-6 E-torque motor. There’s a whole lot more going on with that truck than just a factory-equipped tonneau cover.

I don't follow your point. The HFE package represents everything they could realistically do to maximize the fuel efficiency including all of those things. Including the tonneau.

The tonneau by itself isn't responsible for all of the efficiency improvements but it would not have been included as a part of that package in particular if it did nothing for fuel efficiency.

 

[corneileous]

I don't follow your point. The HFE package represents everything they could realistically do to maximize the fuel efficiency including all of those things. Including the tonneau.

The tonneau by itself isn't responsible for all of the efficiency improvements but it would not have been included as a part of that package in particular if it did nothing for fuel efficiency.

The discussion at hand is about the very minuscule advantage of increasing fuel economy with a tonneau cover on virtually whatever truck; you threw in Ram’s HFE trim which is all about squeezing as much MPG’s out of a pickup as one could possibly muster. You presented this as a benchmark to try and prove a point to when someone made the comment that if tonneau covers really helped to save on gas, they’d be putting tonneaus on every truck just because this one is the only one that comes with a factory cover. It’s a moot point.

The cover on this HFE truck is just one..... minute little aspect of what this truck is all about when it comes to saving at the pump.

I’m not trying to be an *******, I’m just simply trying to say that putting that much emphasis on the HFE’s factory tonneau cover is short-credited because that cover is only one very small aspect of like five things it has going for it to see upwards of 27 miles per gallon.


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[kurek]

Right it works which is why they put it on at the factory. I don't see the argument. They want the truck to get better mpg so they put a tonneau cover on it because it works.

 

[corneileous]

Right it works which is why they put it on at the factory. I don't see the argument. They want the truck to get better mpg so they put a tonneau cover on it because it works.

Lol no, they put it on there to just be one more thing- irregardless of how minuscule a cover actually helps fuel economy- to push that number up as high as they possibly can for the marketing of it. Heck if I was one of the brains behind this, I’d be going the extra mile and making nitrogen-filled, very least-rolling-resistant tires as standard, a redesigned lower hanging front clip, AGS (unless it’s already got it), undercarriage cover, maybe some side skirts to minimize drag and maybe drop the suspension down an inch with the aid of the four-corner air ride opposite of like what they did with the Rebel by raising normal ride height up an inch for that taller off-road look, so that they could take advantage of the eco mode on the air suspension when it drops almost another inch once you hit highway speed.

Again, the tonneau cover is just ONE thing.




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[rlampman]

My experience is yes, slightly. I track my mileage regularly and the before and after showed about 0.5 mpg better with the BakFlip hard cover. I put it on for security but it did help a little. Based on other factors (lift, tires, driving style, etc) you may not see a difference. I have a RCSB 2wd that is lowered. I found that the 4/6 lowering gained a good 1 mpg while the muffler delete also another 1 mpg. My CAI didn't provide any improvement. I did all these changes at different times so I did see the difference. The most improvement was really from driving style. I can get a consistent 18.5-19.5 on my regular commute. More city obviously brings that down quickly. I have had the fiberglass covers on many other trucks and didn't see a difference. I agree with others that the weight probably canceled out any improvements.
I would say overall if you want it for other reasons do it and it won't hurt your MPG. You may get some benefit.
Rod