Tonneau Cover Range Improvement numbers

[ZeusDriver]

That is the cheapest cover I've heard of, good buy.

After being stunned by the offerings at Leonard, I checked Facebook marketplace, and found it in near perfect condition. The type is about 250 brand new.

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[tearitupsports]

I don't think the cover makes any difference. That being said, I have had a Bak X4S since the first week of owning the truck and 63,000 miles later I still have an all time efficiency of 2.3 mi/kWh.

 

[PJnc284]

I don't think the cover makes any difference. That being said, I have had a Bak X4S since the first week of owning the truck and 63,000 miles later I still have an all time efficiency of 2.3 mi/kWh.

A X4S was also my first purchase. Had it for about 18 months. I mainly got it because I liked the look of a covered bed better and it beats having to push snow out of the bed the once every 5-10 years we get any. Can't say I've noticed any discernible difference in mileage which lines up with every test I've seen. Shame mythbusters didn't do this test when they did their tailgate up v down. I averaged 2.2 at 60mph and 1.8 at 75 the month before I got it and still get the same. A brick is a brick is a brick after all.

Asked chatgpt to give me a more aerodynamic lightning. I ran out of tries to make it 4 door

 

[RLXXI]

I started covering my truck beds for one single reason, to keep asshats from using my truck as their garbage can. Too fking lazy to keep holding that empty until they get to an actual trashcan, no they just drop it in the bed. Infuriates me would be describing it lightly.

 

[Timeless Epoch]

A X4S was also my first purchase. Had it for about 18 months. I mainly got it because I liked the look of a covered bed better and it beats having to push snow out of the bed the once every 5-10 years we get any. Can't say I've noticed any discernible difference in mileage which lines up with every test I've seen. Shame mythbusters didn't do this test when they did their tailgate up v down. I averaged 2.2 at 60mph and 1.8 at 75 the month before I got it and still get the same. A brick is a brick is a brick after all.

Asked chatgpt to give me a more aerodynamic lightning. I ran out of tries to make it 4 door

Reminds me of the Ranchero.

 

[JMD359]

I can obsess about this stuff... but obviously if I were really concerned about vehicular efficiency, I'd be driving a Prius instead of a Lightning.

So, the theory is this: a tonneau cover lowers the Cd (coefficient of drag) of a pickup truck. That is almost universally true, for reasons that are probably intuitively obvious. The tailgate is an obvious apparent wind catcher. Try to carry a sheet plywood with the flat side facing the wind on a gusty day, and you will appreciate aerodynamic drag.

I've linked a study by SEMA that squares with my understanding of aerodynamics, and especially vehicular aerodynamics.
https://www.agricover.com/downloads/pdf/2007_windtunnel.pdf

Aerodynamic drag becomes increasingly dominant with increases in speed (going up at the square of speed, unlike rolling friction, which stays nearly constant). Power required, therefore, goes up with the cube of speed, (because you are both going faster and pushing harder). Power times time = energy usage. Range increases by the same factor as claimed fuel mileage increases.

If you do a lot of highway driving, (and charge at the robber barons' fast chargers) then a tonneau cover can justify its cost even if you have no other use for it. The range reduction you might imagine from the increase in weight is not measurable, because even the rigid covers are so light. (Do you stick your nose out the window and aim your sneezes backwards to give the truck a little boost?).

My range seemed to improve by about 10 miles (about 5%) after installing my ($100) fold up tonneau cover. However, I was driving fast on the day that I checked, and I don't bother to check on slow driving days, because I know there is no measurable difference. So read the article if you are so inclined, and figure in your style of driving. No "average" gain in range will likely apply to your use case... and my presumed gain won't apply either, unless you happen to drive exactly like me... on the same roads... at the same temperature... in the same wind conditions.

AC and heat have a significant effect on range, as does terrain and many other things. (That is why I used the word "seemed" above -- a definitive, reliable, repeatable test is quite difficult, if not darn near impossible.)

Related: My front air dam extension (the retractable part that extends at 40 to reduce aero drag) fell off a while ago, and I have not been able to detect any difference in range. I tend to drive at close to the speed limit. Maybe if I drove at 20 over all the time, I'd notice a difference.

My seat of pants tells me the cover takes away range slightly . I run about 50 percent of the time without it since I use thumbed a lot for firewood and large items . I could be wrong but either way it’s insignificant .

 

[zakress]

My Lightning has had a cover on it since day 1, so I can’t speak to its difference. On my 12th gen, the tonneau made a 0.18 mpg difference which could easily be had by driving 3-5 mph slower or accelerating slower or a tailwind or any number of things.

The one very noticeable difference was the smoothness of the air with the rear window open. Prior to the tonneau,, there would be a lot of noise and turbulence through the window, but almost none once the cover was installed.

 

[Rayden]

Shame mythbusters didn't do this test when they did their tailgate up v down.

THANK YOU! I knew I'd seen something about this before. Didn't they conclude that the drag was actually WORSE with the tailgate down? That with the tailgate up, it created a sort of turbulent ball of air that kept the flow from sucking down into the bed. I seem to remember thinking that all those dudes with the tailgate net had wasted their money.

 

[Rayden]

Try to carry a sheet plywood with the flat side facing the wind on a gusty day, and you will appreciate aerodynamic drag.

Ha ha, so true! You just reminded me of a time when I almost got my ass blown off a roof! Grabbed the sheet of plywood from the guy handing it up from below and as I turned, the wind caught it. I dropped it and fortunately did not hit the guy nor fall off myself. Lesson learned.

 

[K6CCC]

THANK YOU! I knew I'd seen something about this before. Didn't they conclude that the drag was actually WORSE with the tailgate down? That with the tailgate up, it created a sort of turbulent ball of air that kept the flow from sucking down into the bed.

Yes. That was the MythBustes conclusion.

 

[Rayden]

Yes. That was the MythBustes conclusion.

What's funny is that I just did a quick search and these things are still available to buy.

 

[Lytning]

I suggest obsessing over something easier to understand and control ... like peace in the Middle East.

But, if you want to do a deeper dive on this subject ... my Rhino Rack Rails have VORTEX bars for SUPERIOR AERODYNAMICS!

 

[jimfigler]

I can obsess about this stuff... but obviously if I were really concerned about vehicular efficiency, I'd be driving a Prius instead of a Lightning.

So, the theory is this: a tonneau cover lowers the Cd (coefficient of drag) of a pickup truck. That is almost universally true, for reasons that are probably intuitively obvious. The tailgate is an obvious apparent wind catcher. Try to carry a sheet plywood with the flat side facing the wind on a gusty day, and you will appreciate aerodynamic drag.

I've linked a study by SEMA that squares with my understanding of aerodynamics, and especially vehicular aerodynamics.
https://www.agricover.com/downloads/pdf/2007_windtunnel.pdf

Aerodynamic drag becomes increasingly dominant with increases in speed (going up at the square of speed, unlike rolling friction, which stays nearly constant). Power required, therefore, goes up with the cube of speed, (because you are both going faster and pushing harder). Power times time = energy usage. Range increases by the same factor as claimed fuel mileage increases.

If you do a lot of highway driving, (and charge at the robber barons' fast chargers) then a tonneau cover can justify its cost even if you have no other use for it. The range reduction you might imagine from the increase in weight is not measurable, because even the rigid covers are so light. (Do you stick your nose out the window and aim your sneezes backwards to give the truck a little boost?).

My range seemed to improve by about 10 miles (about 5%) after installing my ($100) fold up tonneau cover. However, I was driving fast on the day that I checked, and I don't bother to check on slow driving days, because I know there is no measurable difference. So read the article if you are so inclined, and figure in your style of driving. No "average" gain in range will likely apply to your use case... and my presumed gain won't apply either, unless you happen to drive exactly like me... on the same roads... at the same temperature... in the same wind conditions.

AC and heat have a significant effect on range, as does terrain and many other things. (That is why I used the word "seemed" above -- a definitive, reliable, repeatable test is quite difficult, if not darn near impossible.)

Related: My front air dam extension (the retractable part that extends at 40 to reduce aero drag) fell off a while ago, and I have not been able to detect any difference in range. I tend to drive at close to the speed limit. Maybe if I drove at 20 over all the time, I'd notice a difference.

There is no improvement. 3 years with this truck with and without the tonneau and ive seen no difference. This has been tested by many others. Any change you saw was due to other factors.

 

[Wattsgas]

2023 Ford F150 Lightning Yearlong Test: AeroX Fastback Roof Road-Trip Range Results Are In.


Guess there is a reason for the Cybertruck looking like chevy avalanche.

 

[chl]

I drive both a Prius and the Lightning.
The lightning gets better miles per dollar spent (gas vs electricity).
And the sticker says my Lightning gets a combined 68MPGe, while our 2015 Prius hybrid sticker says a combined 50MPG.

{EDIT: also drive a 2012 Nissan Leaf sticker: 99MPGe}

Anecdotal evidence about your combined mi/kWh is not going to be conclusive because where aerodynamics (CD) takes dominance is at highway speeds.

At slower speeds friction is the largest component in determining efficiency, so I've read anyway.

Also the effect may not be determinable by comparing your highway driving with and without the tonneau, because the difference may be slight, but adds up as the miles pile up.

Putting the truck in a wind tunnel and seeing what happens with and without the tonneau cover seems like the way to answer the question - but will it be enough for us to even notice with combined highway and city driving? I am doubious.

Race cars use air dams and spoilers to have an edge.
Airplanes use a streamlined shape, a smooth surface, wing design (adding winglets), eliminate gaps on control surfaces, etc., to reduce drag.

I doubt there is much we could do to improve the box we drive down the highway to reduce drag, whether or not the tonneau cover helps a tad or not.

If you want a low drag vehicle, check out the Aptera (going into production soon, I hope). It has a cd of 0.13, better than even the Tesla model 3 which reportedly has a cd of 0.23.



The Lighting cd - I was almost afraid to look it up - with a tonneau cover is: 0.430 - with the AeroX fast back bed cap: 0.339.

That gap between the cab and the bed is a significant source of drag, so they tell me.
One reason why adding something to cover that gap, like the AeroX cap (the way airplanes do) may give the most improvement.

But I'm not sure we'd notice the difference... or settle the debate.

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