if it hurts mileage it's because of the additional weight. so i guess the lighter the better. The guys running hard covers probably see the decrease. I think it's been proven that with the tailgate up, a pillow of air forms in the bed of truck that the "rest of the incoming air" rolls off of, essentially an invisible cover. It's when people drop the tailgate, they lose that pillow of air and it actually hurts mileage (which is why I laugh when i see people still doing this).

Regardless, i think the gains/losses will be minimal, i couldn't imagine more than a +/- 1mpg. I would get a cover for practicality purposes, not just to increase MPG. If you do get one, and are worried about mpg, go light as opposed to heavy.

 

I was looking at the fabric roll up ones as they don't trade off the useability of the bed for carrying large stuff.

 

I think u should be good to go with one of those

 

You should get the cover you like and can afford. My opinion is that the mileage isn't going to be a huge factor. If it was, you would be driving a prius! lol

 

I don't drive a Prius because the Prius is obsolete. I drive a Volt on a daily basis except in the winter.

As for the rest of my vehicles, I still strive to obtain the best possible fuel economy out of them. I took a trip to Minot and back in the Ram yesterday, and managed to just squeak out an even 20 mpg reading on the mileage computer.

 

MythBusters & a couple other programs have done tests to see just which gives better gas mileage, tonneau, no tonneau, tailgate dropped, tailgate removed, tailgate net, etc. etc.
Personally i watch NasCar truck racing & they all have covers, but they are not too worried about MPG & they don't have a truck bed floor, so they do it for looks
I have a cover so that people don't use my truck bed as a dumpster & they don't see what i carry in my truck bed, out of site, out of mind, so to speak. It also keeps water, dirt, dust, bird dung, leaves, etc. out of the bed.

If i am losing 1/2 gallon of gas per 500 miles, because of a tonneau, it is worth it to have one

 

I have a cover so that people don't use my truck bed as a dumpster & they don't see what i carry in my truck bed, out of site, out of mind, so to speak. It also keeps water, dirt, dust, bird dung, leaves, etc. out of the bed.

YEP!!!! Keeps most your stuff in the bed out of the weather/dry. Works great for luggage, etc,,,

If you only want to improve your mileage, you will never see a big enough return on your investment to offset the cost of the cover, but, there a lot of other reasons/benefits involved with a cover.

I bought an Access 'Lorado' in early '10,,, VERY happy!

http://www.autoanything.com/tonneau-covers/60A1952A0A0.aspx

 

I wish I could recall the link to post here, for a nice study done on this very question. The study compared MPG with no cap, cover etc., with a cap & then with tonneau covers. The gist of the study results indicated tonneau covers gave only a very slight increase in MPG over no covering at all and caps gave only a slight decrease in MPG. Bottom line is if you need or want covering for your bed whether in a tonneau cover or cap form, MPG should not factor into the equation since the differences were insignificant.

 

I know this may sound a little weird but heres my input on this. I just bought my ram and it had a tonneau cover on it, its older and just fabric / vinyl and a little worn out but no rips or tears just older and maybe a little stretched. At faster speeds I could see the cover moving in the wind, kinda up down up down etc... air was somehow still getting under there or it was no longer tight enough and the air on top was able to push it down at thruway speeds. I found a cheap fiberglass cap on craigslist and just went to go pick it up the other day. On the way there was getting a horrible 14 mpg on the way to pick it up. On the way back I never went lower than 14.5 mpg. (still horrible lol) Maybe its just coinencidence but Im wondering if getting rid of that buffeting on the tonneau cover and smoothing out that air flow at the rear helped the mpg a litte?

 

If I remember correctly, the Mythbuster testing confirmed that the best setup is to remove the tailgate and install a tailgate net. That gave the best MPG over anything else (albiet hardly noticeable). Get a cover U need to keep things dry and clean, everything else (gaining better MPG) is of no real use in the real world. BTW a Government Motors VOLT...really! I know U probly picked one up with that big discount. IMO the Volt is obsolete, bring back the small diesels, better yet allow us Americans to buy the diesels that the rest of the world already have! A VW Polo will get 75mpg+ all day long! Sorry, pet pieve of mine :doh:

 

If that is a pet peeve, then you need to get rid of your truck. Chrysler was also bailed out by the government, and Fiat has not yet been able to buy out the rest of the feds holdings in the company. As for the 75 mpg of the Polo, I'll take zero gas consumption over 75 mpg any day of the week. Last time I put gas in the Volt was last August, and I still have well over 3/4 tank. Not everything that the oxycontin addict says is true. What he will not admit to is that the Volt was under development before obama ever became the communist party's wet dream of being president. Those tax credits are also the work of none other than George W. Bush.

The right and left wing talking heads on T.V. and the radio are the governments best friend. Both sides exist solely to keep those foaming at the mouth solidly in their protracted rage, and fighting with each other about who is better than who. Meanwhile, the government continues to rob us ALL blind, and laughs at our gullibility and ignorance about what is really going on in dee sleaze.

 

Again U are right it is Hilux (sp) however it's spelled I want one. I don't hate the product (Volt) what I don't like is the way it was presented, discounted and sold with gov. help. If it is such a great vehicle (which I think it is BTW) it would have sold itself in the free market but...:4-dontknow:. A small diesel for me would make more sense. I don't live or work anywhere near a major city and all my driving and work is very rural and hilly, with lots of dirt rds and broken pavement hauling equipt. (hence nice to have a Hilux). Problem now is the diesel engine has been strapped with so much government "clean" air garbage it makes the cost much greater to have one here in the US. Doesn't make sense to have a "clean" diesel burn twice as much fuel (DPF,Urea, EGR) to get the same or worse mpg and be better for the environment.:thk: Anyway, glad U enjoy the Volt. I think its ahead of its time and a good vehicle in its own element just like the Honda Insight (sp?), which didn't sell well when it came out either.

 

Motor Silk

Has anyone tried Motor Silk engine oil additive in an attempt to boost fuel economy in the 5.7? Results?

 

There's a reason the HFE model comes standard with a tonneau cover.

From http://www.edmunds.com/fuel-economy/improving-aerodynamics-to-boost-fuel-economy.html :

"It turns out the biggest gains are to be found on pickups — not by dropping the tailgate (a common misconception), but by installing a tonneau cover. "A tonneau cover improves the aerodynamics dramatically — on all pickup trucks," according to Ford's Wegryn. "In general, a tonneau cover can provide a drag reduction of 2 to 7 percent, depending on cab style, box length and overall vehicle Cd. Average fuel economy improvement ranges from 0.1 to 0.3 mpg." From an aero standpoint, it doesn't make a difference if you choose a soft or hard cover."

 

I have seen right at 1mpg improvement with the cover installed on my Dakota R/T. I have not tried it with my Ram yet mostly because it's a PITA to remove the cover.

 

1. Mythbusters never tested covers. They tested tailgate myths.
2. The "air bubble" created in the bed is due to turbulence. Turbulence is not ideal.
3. "The weight hurts the mileage" :doh:Seriously? These trucks weigh close to 5,000 pounds. Do you really think a 30-50lb. cover is going to affect MPG more than the aero improvements? The difference in weight on an empty or full 34gallon tank is 192lbs. If 30lbs. had such a detrimental effect on mileage for a 5,000lb. truck they wouldn't have put tanks that can hold that much fuel.

 

With modern day aerodynamics, it really doesn't matter:

AS you can see the air doesn't even go into the bed. On older trucks, it's been shown (in wind tunnels) that with the tail gate up, the wind hits the tailgate, swirls up, and forms a high pressure zone that the air rides over (much like the above image, actually). I think tonneaus for MPG is a myth. Buy one because you need or want one, not for MPG!

 

With modern day aerodynamics, it really doesn't matter:

AS you can see the air doesn't even go into the bed. On older trucks, it's been shown (in wind tunnels) that with the tail gate up, the wind hits the tailgate, swirls up, and forms a high pressure zone that the air rides over (much like the above image, actually). I think tonneaus for MPG is a myth. Buy one because you need or want one, not for MPG!

Great graphic, I think this addresses the debate very well.

 

The Volt may be cheaper until the batteries go out on it. From what I've read they don't have a long life and when they have to be changed out it actually pollutes the environment more than the same vehicle running a gas engine. And then you have the limited range and shortage of recharge stations and the cost of plugging in to them. I will stick with my gas power, thank you very much. Besides it's not Mopar.