Do I really need/want a bed cover?

[dcmdon]

I carry guns, skis, and luggage far more often than I carry lumber. So something secure is a must have for me.

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[doc-ketamine]

This is a first. How does a cover drop the mpg? I would have figured it would help MPGs

First, the gladiator has the aerodynamics of a shoe made out of bricks. One of the ways the aerodynamics at higher speeds or improved is the air coming up over the cab drops straight down into the bed and forms of vortex, or cushion of air. This cushion of air reduces drag and improves the overall aerodynamics of the vehicle. This doesn’t really happen until about 55 mph or higher. So second, as our speed increases our miles per gallon decrease. You may have noticed this on the highway - anything over 65 piles miles per hour and your fuel economy will decrease. With tonneau cover on, you don’t get that cushion of air over the bed so the aerodynamics are affected.

There was an episode of MythBusters a few years ago that went through this, but they only used one truck. They did test with a bed open, with the cover on, with the tailgate up, with the tailgate down, and with a net. The best mile per gallon gain, was with a mesh tailgate, interestingly enough.

Plenty of folks on the Internet will tell you that you’ll get a small improvement in your fuel economy with a tonneau cover, and if you do, that’s great. Just never buy a tonneau cover with gain in fuel economy being the main goal. I have mine to protect my gear, out of sight out of mind.

 

[Jocww]

First, the gladiator has the aerodynamics of a shoe made out of bricks. One of the ways the aerodynamics at higher speeds or improved is the air coming up over the cab drops straight down into the bed and forms of vortex, or cushion of air. This cushion of air reduces drag and improves the overall aerodynamics of the vehicle. This doesn’t really happen until about 55 mph or higher. So second, as our speed increases our miles per gallon decrease. You may have noticed this on the highway - anything over 65 piles miles per hour and your fuel economy will decrease. With tonneau cover on, you don’t get that cushion of air over the bed so the aerodynamics are affected.

There was an episode of MythBusters a few years ago that went through this, but they only used one truck. They did test with a bed open, with the cover on, with the tailgate up, with the tailgate down, and with a net. The best mile per gallon gain, was with a mesh tailgate, interestingly enough.

Plenty of folks on the Internet will tell you that you’ll get a small improvement in your fuel economy with a tonneau cover, and if you do, that’s great. Just never buy a tonneau cover with gain in fuel economy being the main goal. I have mine to protect my gear, out of sight out of mind.

I actually got better mpg with my decked system than without it, so i am hoping the cover will get it back.

 

[Jeeperjamie]

This is a first. How does a cover drop the mpg? I would have figured it would help MPGs

It doesn't help or hurt MPGs, this has been discussed numerous times. A bed cover will make no difference either way, just like riding with your tailgate down doesn't improve mpg's. If a bed cover would improve Mpg's then FCA would have put them on a JT standard to help them meet or exceed mpg standards. These post are funny though to read.

Look up myth busters I think they did a episode that said it made little to no difference either way

 

[NERokToy]

The Wind Tunnel Study
In 2007, the Specialty Equipment Market Association (SEMA) conducted one of the most scientific studies on this question. Their team tested four trucks of different makes and 13 different tonneau covers. The trucks tested were:

• Chevy Silverado truck bed cover
• Dodge Ram 1500 truck cover
• GMC Sierra bed cover
• Ford F-150 bed cover

The 13 tonneau covers included all different materials of soft and hard covers. There were a variety of styles including roll up, retractable, folding and hinged. They decided not to release the data about any specific tonneau brands they used.

They tested the trucks in a full-size wind tunnel. They took their experiment to the AeroDyn Wind Tunnel in Mooresville, North Carolina, which is often used by NASCAR. The tunnel let them test how the trucks performed both with and without tonneau covers.

Their goal was to measure whether the tonneau covers reduced drag.

The wind study tunnel found that each truck had less drag when using a tonneau. The results weren’t huge, but they were measurable. On average, using a tonneau cover led to a 5.7% reduction in drag. That reduced drag meant about a 1.8% increase in fuel efficiency.

Even though 1.8% better gas mileage isn’t massive, it definitely makes a difference over a year of fueling up your truck. The verdict of the Wind Tunnel Study? Using a tonneau cover could give you a modest increase in savings on gas.

1.8% is going to save you maybe $60 over the course of 20k miles. Wanted to share this before anyone started questioning myth busters

 

[HankB]

First off I am not going to get into the air flow discussion, other than to say past work experience with actual vehicles has taught me that lab and experimental test results while useful, do not often translate into equal real world results.

More importantly, there is a whole cost benefit analysis to be considered of fuel mileage savings/secure storage space. I too carry shotguns, or expensive fishing tackle (tuna reels/rigs) in the back of the Gladi and added large item security is a plus. For that reason, I went with the bak flip hard cover. Is it a perfect secure solution? No, but good enough to go into a bait shop for ice, or go use the mens while on the interstate on my way to a sporting clays shoot and not worry about the stuff in the back.

Besides security, the particular hard cover I got provides pretty good weather protection from rain and snow. I have had experience with soft covers and caps and think the hard cover meets a happy medium between nothing/soft cover and full cap.

 

[Dougstdig]

While I’m not delusional in thinking it’s 100% safe, there is peace of mind regarding theft, water damage and stuff being blown out going down the road. Knowing most water and dust won’t get in saves time and $$$ having to continually clean things. I’m on the road the vast majority of the time, so just unloading is not an option in my case.

 

[ShadowsPapa]

First, the gladiator has the aerodynamics of a shoe made out of bricks. One of the ways the aerodynamics at higher speeds or improved is the air coming up over the cab drops straight down into the bed and forms of vortex, or cushion of air. This cushion of air reduces drag and improves the overall aerodynamics of the vehicle. This doesn’t really happen until about 55 mph or higher. So second, as our speed increases our miles per gallon decrease. You may have noticed this on the highway - anything over 65 piles miles per hour and your fuel economy will decrease. With tonneau cover on, you don’t get that cushion of air over the bed so the aerodynamics are affected.

There was an episode of MythBusters a few years ago that went through this, but they only used one truck. They did test with a bed open, with the cover on, with the tailgate up, with the tailgate down, and with a net. The best mile per gallon gain, was with a mesh tailgate, interestingly enough.

Plenty of folks on the Internet will tell you that you’ll get a small improvement in your fuel economy with a tonneau cover, and if you do, that’s great. Just never buy a tonneau cover with gain in fuel economy being the main goal. I have mine to protect my gear, out of sight out of mind.

>> With tonneau cover on, you don’t get that cushion of air over the bed so the aerodynamics are affected.<<
The cover is that cushion............

GM and others have done more rigorous testing and found that the tonneau cover DOES improve mpg.

Real testing, not just short drives on a highway in a single truck, show improvements. These are longer studies using more covers, more trucks.
And one reason MB may not have been impressed with their test with a cover - soft covers help more than hard covers.

And finally, this from GM (others have said the same thing - covers help, soft covers help MORE)

 

[geneinhouston]

While I’m not delusional in thinking it’s 100% safe, there is peace of mind regarding theft, water damage and stuff being blown out going down the road. Knowing most water and dust won’t get in saves time and $$$ having to continually clean things. I’m on the road the vast majority of the time, so just unloading is not an option in my case.

i like the look of this one! can you send a link? maybe amazon? and also how easy was it to install because i suck at stuff like this haha!

 

[Blackjeepjk]

I needed something to cover spare laying in bed. So I went with the tyger roll up. I think it was $169 on Amazon.
it was either that for $169 or a spare tire rack with cover for $350+.

as far as gas mileage goes, surely no one of us on here bought a jt for improved gas mileage much less the tires, tents, and other accessories we carry around. ?

 

[geneinhouston]

I have been asking myself the same question since i bought my Gladiator haha!
I don't NEED it...they kinda look cool in my opinion...just need to decide how much i want to spend as the soft ones are super cheap in my opinion and the hard ones are pretty pricey.
i will look at the forums suggested for a used one maybe

 

[doc-ketamine]

GM and others have done more rigorous testing and found that the tonneau cover DOES improve mpg.

Real testing, not just short drives on a highway in a single truck, show improvements.

I don’t doubt @ShadowsPapa of course, and appreciate his insight. I did see the GM studies but also saw articles discounting GM’s studies as they had only tested 4 vehicles and it wasn’t longitudinal … but this could be considered hearsay in any case.

I’d trust ShadowsPapa more than me.

 

[ShadowsPapa]

as far as gas mileage goes, surely no one of us on here bought a jt for improved gas mileage

Uh, actually, I did. My Chevy could get 20 if I kept it to 50-55 mph, but in real world driving, 14 was more like it. Towing was 11-12 mpg.
My Ford was even worse. Head wind, tail wind, loaded, empty, towing, not towing - 12 mpg, that was it.
My JT blow's 'em all away. I towed 5,000 pounds of car on my car hauler (total weight) and got average of 13.9 there and back. It is more typical to see 13 and a bit over with that same load.
Yeah, it gets better mpg than my WJ did, and better than any of my other trucks.
That is indeed one reason I went with the JT.

When traveling with that truck, either with my wife across the country, or myself to swap meets, etc. - I like the cover and being able to "lock it" with stuff in the back. Luggage, parts, stuff from shopping, whatever. At a swap meet, I keep stuff secured in the back away from prying eyes, and traveling we can stop at a rest area or to gas up or eat, and figure it's not so easy to get in and take anything. They don't even know if there's anything back there to mess with taking.

 

[ShadowsPapa]

I don’t doubt @ShadowsPapa of course, and appreciate his insight. I did see the GM studies but also saw articles discounting GM’s studies as they had only tested 4 vehicles and it wasn’t longitudinal … but this could be considered hearsay in any case.

I’d trust ShadowsPapa more than me.

When I had my silverado, I noticed a slight difference in mpg cover rolled back and on, covering the bed, vs cover removed or even rolled up.
I figured hey, that cover appears to be helping. I submitted my observations around and was quickly shot down.
Naw, I was pretty sure of what I was seeing over the years of owning and driving that truck, so I set out to either prove I was imagining things - wishful thinking, or that I was was correct, even if only a tiny bit.

One of the sources of info I found was a study using multiple truck makes/models - Chevy, Ford, Ram. The one snipped I posted above in my prior message today was from that study.
So here's their processes, the trucks used, and who participated -

And unlike Mythbusters who only did one run each time at 25 and at 55 - this test was done at varying real-world speeds -

Even MotorTrend makes this comment -

Covered bed previously proven more efficient.
Pretty much sums it up.

This is from GM's testing -

GM has also found that the gap between the front of the truck's bed and the back of the cab creates drag - closing that gap reduces drag.

 

[Jcsii]

Your weight concern is understandable but unfortunately I think everyone pretty much ignores it. Unloaded (no camping gear), with just myself, diamondback cover, Billie Bars rack, and awnings I weigh in at about 6000lbs. Only other mods are stubby bumper and winch.

The diamond back is pricey but probably one of the most secure if that really concerns you and can be load directly if need be. Also comes off in 10-15 mins if you need the bed.

I really like the fact you don't loose a lot of rear visibility with the billie bars.

Really just comes down to personal preference.

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