Surprising Result: Here’s What Happens To Your Truck’s MPG When You Install A Topper!

( tfltruck.com/ ) It's an age old question - does having a topper installed on your truck actually help or hurt your MPG? In this video, Andre investigates exactly how much the fuel economy shifts when running with and without a topper on our shop truck - the 2004 Ford F-150 with a 4.6-liter V8.
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#Topper #MPG #FuelMileage

[@mcoutis]

save yourself 10 minutes. It's exactly the same.

[@michaelbryant2071]

Thanks. Out at 1:58.

[@22891690]

The real mvp

[@Notacuallyash8745]

The hero we needed 😂

[@matthewgunter2207]

Thank you!

[@KingSolrac]

real

[@jeninjeans]

I can just imagine the workers at the gas station. "This guy again? He's been here like 3 times today. He must get shitty mileage"

[@kdrapertrucker]

They probably say "there's andre again, must be doing a video for TFL truck"

[@caseym5017]

It's Colorado they're probably too stoned to even notice. 🥴

[@NickAlati]

I have the super duty with the V10 and the gas station people do say that about my truck LOL

[@brianrvd]

Gas stations must see hundreds of white pickups a day.

[@mikescooby7625]

You must be old ,no one works at a gas station anymore. . At least no one that would notice you filling up

[@travelcampingblacksmithing786]

I recently added a camper shell to my personal DD pickup. It's a mid rise shell. I went from 14.7 average mpg to 16.2 mpg with the topper. This is a months worth of mpg calculations with the topper

[@networth9151]

I wonder what the gas mileage would be if you had the tailgate down vs. the tailgate up?

[@donaldpiper9763]

@@networth9151It would be about the same savings on gas . I’ve drove pickups for for 50 year’s and that’s the easiest way to improve gas mileage because it reduces drag and increases airflow. You’ll never get great gas mileage with a truck because of gears and weight,height ect. but a couple of gallons adds up .

[@travelcampingblacksmithing786]

@@networth9151 mileage would be worse. There are plenty of videos explaining why. Aerodynamics get worse with the tailgate down

[@bradgriffith4231]

Years back there was a mini pickup sports car racing group that did tests. Lap times were identical with the tailgate up or down. The air doesn't ever see the tailgate. Try opening your tailgate & throw some aluminmum cans in the bed. They don't blow out, but instead, shuffle around right at the front of the bed right below the cab's roofline.@@networth9151

[@wompstopm123]

if your topper had a tail that stuck out the back and extended downwards to cover the bumper of the car you would save another 1 mpg

[@drwisdom1]

There are three primary benefits to toppers: protected storage, racks on top, and most importantly making the pickup more balanced so it handles better in snow.

[@dave5176]

Protected storage. Basically, another place for thieves to break into. Racks on top drag your gas mileage down.

[@vasmajority45]

​@@dave5176must suck to live in the city

[@ronl1633]

@@vasmajority45 Yes it's really not what it once was.

[@Joe-hz1nw]

@@vasmajority45ehh, depends on the city. I’ll be able to retire at least 10 years sooner because of living in a suburb, working close to a large city with way higher pay. I’ll also be able to buy land and a cabin to get away. Commute only takes 20 min or so. To each his own.

[@matthewhuszarik4173]

Protected storage I’ll give you but a rack on the bed is much better than a rack on a cap. As far as weight a couple of sand bags in the winter makes far more sense that carrying a cap around all the time.

[@luckytrapper7656]

That 4.6 motor is a great motor. The 18 years of owning my f150 with the 4.6 , I didn't have any issues besides basic maintenance of course . It's unbelievable how the truck manufacturers stop making a proven motor and replace it with something else that usually is junk.

[@BIKEMAN21]

If its tried and true you know 20 years later they will make a leaking, rattling junk version because it costs less to make.

[@bloodbushcraft2467]

It sucks they all do that shit. I wonder if it wasn't for all this EPA garbage if they'd have kept some reliability

[@acdii]

Have the same 4.6, though cammed for passenger car, in a 1995 Grand Marquis. Starts and purrs at the touch of the key to this day. Really good reliable engines.

[@ShyaMiss]

Its incredibly common that the hoops they have to jump through for changing EPA regulations, and cafe standards, both take a dramatic toll on reliability. Many of the engines, regardless of manufacturer, have the capability to go MANY trouble free miles. It's the issues that arise from egr, pcv (routed into the intake), dpf and scr (diesels), and often times the tuning required to run clean enough for emissions standards, all these things take their toll on an engine. I am all for vehicles that arent gross polluters. But on the other hand, who likes to be stranded somewhere simply because reliability matters less than what the EPA decrees is allowable for the time being?

[@tedschmitt178]

Because the old engines become obsolete. Why do you think Ford stopped producing the Model T engine? It’s called engineering, and the replacements are NOT always junk.

[@rodneywelch3556]

I noticed an immediate improvement with the cap on my truck. The display reads the average mpg over a 400 mile baseline that you can reset, but I didn’t reset. Just letting it run and watching that number go from 17.9 to 18.6 after about 200 miles makes me smile. Hoping to see a new normal over 19 after she taps out at 400 miles!

[@greentland]

Easily the best reviews to be had anywhere. No silly music, no Jeremy Clarkson wannabees, no Doug Demuro rattling on about door locks for 45 minutes, just pure and simple objective testing. Perfection.

[@calebmoran5580]

Amen

[@scenicdepictionsofchicagolife]

Doug demuro is the shit. If you're watching his content for usefulness about cars he reviews you're doing it wrong. His content is parodical in nature. Its not meant to compete with Edmunds or TFL, etc.

[@greentland]

@@scenicdepictionsofchicagolife We'll have to agree to disagree.

[@jamesbarrick3403]

Actually this could easily be a 60 short video... that would be perfection. I just FF to the last 2 minutes on all of these.

[@jh748]

@@greentland I have to agree with @Scenic Depictions. Demuro previews in detail anything from a Pinto to a Rolls to an F150, not just trucks which is why some of his content generates as much as 1.5mil views in just a few days. Absurd comparison.

[@stanleyreynolds7800]

I had an interesting experience with an old V6 Blazer. I put a (pointed prow) rowboat upside down and nose first on top and the gas mileage went from 16 to 20. I left the rowboat on it for a long time, only taking it off when I needed it.

[@rickmcentee9204]

Same speeds, Stanley? It's aerodynamic, but you would think it still produces additional drag, especially at the back

[@stanleyreynolds7800]

I am only reporting what happened. The gas mileage went from ~16mpg to ~20mpg. I didn't change my driving habits.

[@brianaustin1328]

It's nice to know there is no mileage penalty for the added weight and convenience of a topper.

[@Jim-bw8jo]

Although at steady speed it may not make much difference in fuel mileage, consider what the added weight may do for stop and go in town driving.

[@mesanders1113]

@@Jim-bw8jo in my experience even full of tools the weight doesn't make much of a difference in the city efficiency wise. Lots of stop and go reduces mileage significantly even in a smaller light weight 2000 camaro with a ls1 and 6speed manual and driving it slow. My current truck gets relatively the same mileage in the city if it's full of tools or even pulling a heavy work trailer unless I'm driving it crazy then ofcourse it's worse. It does effect acceleration and responsiveness though.

[@ghflcity]

That's if you keep it empty. But I shamefully keep stuff in the back (probably because I'm too lazy to empty it?) adding more weight with the topper. Just a thought.

[@tylerwarren9877]

Thanks Brian, you saved me 10 minutes. I didn't have to watch the video to get the answer and now I can whipe my ass. 🚽🧻👍

[@Icutmetal]

Who thought there would be?

[@wam1388]

Could you do a comparison with a flat tonneau cover, like the roll backs or the tri folds.. They won't weigh nearly as much, will cover the hole of the bed, but not reach the top of the cab to technically be "in the air".. It'd be interesting to know the difference with that, since the weight wouldn't really be a factor..

[@azntactical4884]

I avg 16.4 with a topper, open bed avg 16.5 and with x4 16.8. I do 50/50 hwy and city. I also use cruise control as much as i can and dont beat on the truck.

[@Seriously140]

That was my first thought as well.

[@robadams1587]

Definitely agree with testing of a tri-fold or the like.. I've got a 2019, 2 wheel drive Lariat super crew, with one of the hard cover tri-folds.. Was getting about 20mpg on 4hr trips down interstate with cruise @ 75mph before the tri-fold.. Now with the tri-fold, I'm consistently averaging 22mpg on the same route.. All on 87 octane and at sea level or slightly higher for fyi.. (Just in case that may matter to ya)

[@smileyguyz]

From the research I've done personally, (and lots of sitting in thr bed of trucks on the highway) the bed is a turbulent low pressure zone when moving, and actually doesn't cause much drag.

[@ipdjbt]

Mythbusters did this exact test. Hopefully its on KZbin somewhere.

[@rowdyward]

About 40 years of RV experience here, 20 designing fifth wheels. Experience and wind tunnel tests show the secret is how the wind underneath comes up at the rear and actually pushes you forward. The flatter the rear is, the better push. And someone mentioned drafting behind a truck. If you were to get very close (of course do NOT do this) so the wind would not be able to push the truck but would continue under your trailer and push at the rear you receive a little more assist. Best to keep your distance for safety of course.

[@davesrvchannel4717]

I’m curious how gas mileage would change if you were pulling a camper. I imagine it would be significant difference. I can pull camper with my van much easier than with my truck

[@mupetier]

Thank you Andre. I actually really enjoyed this video. Keep up the good work. I'd like to see taneau cover vs topper vs tailgate down.

[@brucelee64485]

I would like to see this kind of test ran with a box trailer. Run it with the topper on and off and see if the topper helps with fuel exonomy.

[@jetdust]

Exactly what I was going to say!!

[@matthewwilliams89]

Agreed

[@robedmund9948]

If it's a wedge topper it will help a little, but the top of the wedge needs to be pretty high to give you an advantage.

[@shaneb.6328]

Same. I'm get 6 or 7

[@kaldtonde]

This! I get 1-2 mpg more with my v-nose after buying a mid rise shell.

[@amorton94]

This whole video was done right down the street from me right now. It's always weird seeing big channels that are local to you.

[@ThatKiltedGuyDIY]

Yeah it’s pretty cool. I live in Grand Junction but I’ve been over the Ike gauntlet hundreds of times. My channel is only at 130,000 but I’m getting big

[@gittyupalice96]

I've got one for my truck as well, being an 8ft bed.. its a BIG cover. It weighs so much I can't pick it up by myself, and I can also confirm there was no gain in fuel mileage, just a significant reduction in visibility lol. Hence, the reason why mine sits around unless I actually need dry storage.

[@bobd.]

Good comparison, as close as you can get for a short test. Only variable might be the ambient air temperature between the two runs. I'm guessing that you had at least two hours from the start of the first run to the start of the second run. Depending on time of day the air temperature (and density) might have changed. I had a 2005 F-150 4x4 with the 5.4L V8, automatic, and 6.5 foot bed. Don't remember what the axle ratio was but it got consistently between 15 and 17 MPG (depending on the season) with just me and no load in the bed. I had no cap or tonneau cover on that truck. I logged every drop of fuel I put in that truck for 10 years and 114K miles; recording the data in a notebook I kept in the truck. Did that for no reason other than I was curious. I could see when the fuel was switched over from Summer to Winter blend, it was an immediate 2 MPG drop that would show in that first tank of Winter blend. Most of those 114K miles were back and forth to work plus the usual around town driving. My commute was 18.5 miles each way. All back roads and no reduced speeds or bumper to bumper traffic to deal with.

[@DrewEdwardBacklas]

I just like them for hauling a lot of stuff out of the weather and away from prying eyes.

[@ernestpaul2484]

That was always my primary reason for having a topper when I had a pickup. It also served for a place to mount rear cargo lights inside with a switch and rear exterior flood/work/backup lights up high (always had a fiberglass step up topper, except for that one cab level aluminum one that got beat to hell by a wicked hail storm in March of 89'). It was always handy for a place to rack out in out of the weather due to the jobs at the time. Sleeping pad and a make-shift pillow and I was good to go.

[@Saki630]

My friend: After getting out of the clink, I made sure to get a topper to stop the law from eyeing my shit. I am 6years strong avoiding child support and the troopers.

[@jrc0004]

@@Saki630 Nice, bragging about avoiding child support, great father figure.

[@davemiddleditch9741]

Pain in the arse when you're hauling firewood and/or constantly loading/unloading big items. I had a topper on my old truck and ditched it in frustration after 3 months. I just carry a tarp and straps now

[@ernestpaul2484]

@@davemiddleditch9741 It is a pain the ass if you have to haul large items or like you say firewood. But when I had my topper I was younger and stronger, getting it off and on wasn't too bad to do alone. When it was necessary to keep it on, I just grabbed my 6x12 flat trailer for the big stuff. It all depends on the intended reason or use. People change to the appropriate shoes/boots/surf shoes/etc and clothes for the job or event at hand.

[@BIKEMAN21]

Andre excellent job ! keep up the great work !

[@daveharris39]

I learned the same thing when I put an ARE topper on my Sierra. Road trip FL to VA, essentially same mileage as before. Two things may help: - sealing the gap between cab and topper. I can hear the wind blasting between the two (it's a regular cab, so it's right behind my head). The truck had virtually no wind noise before adding the topper. - adding some sort of flat spoiler at the rear of the topper. Look at any modern hatchback or suv, almost all of them have some sort of wing or spoiler on them. Even back in the 70's, station wagons often had a curved (down) spoiler on them.

[@mattf49006]

The rear wing apparatus on SUVs and old school station wagons are to redirect airflow for two reasons..to keep the rear clean and in the station wagons ..exhaust from looping back into the interior with the rear window open...we found that out on a family vacation in 66 when the roof rack had a load lashed down blocking the airflow during a leisurely tour of Yellowstone and a cpl of us kids in the rear seat nearly being gassed out

[@larrycollar1322]

I recently added. A fiberglass topper to my 2012 f150 supercrew. Was hoping to see an improvement in mileage from the 19.2 it has been getting but alas, as you found, the mileage remained the same. Looking at this situation differently, as you pointed out, the topper and all the stuff you now leave it there all the time because it’s protected does weigh a significant amount and yet the mileage didn’t go down. That’s a win in my book.

[@brockspaulding3948]

TLF Truck should do the same test but with a tonneau cover

[@325xitgrocgetter]

And tailgate up verus tailgate down or tailgate removed.....I recall that being a big debate back in the 80s...

[@91CavGT5]

That debate has been resolved. Tailgate down on a modern truck decreases fuel economy. Modern trucks have been designed to have a swirl of air that is “trapped” in the bed. This causes the air coming over the top of the cab to stay above the pocket of trapped air making it go over the top of the tailgate making it more aerodynamic with the tail gate up. When you lower the tailgate, it causes more turbulence behind the cab and this will end up hurting your fuel economy. This is on a modern truck.

[@philtripe]

@@91CavGT5 its too late, we've lost him... he wont take the vaccines anymore either ... his tiny brain has turned into a potato before our very eyes in another sad case of Foxification

[@f1y7rap]

@@325xitgrocgetter Mythbusters already did that, they found tailgate down reduced mileage by a bit. It has to do with the pocket of air that develops behind your truck, and the one that develops in the bed of the truck. kzbin.info/www/bejne/qGTEonuYeZKCb6c

[@ThisGuyRides]

I didn't see noticeable difference with a Chevy Colorado. Right foot makes the most difference in MPG.

[@musicalgreasemonkey]

Appreciate your consistency, efforts and reviews Andre 👍

[@WadeQuick]

excellent post, I kept a topper on my 1997 F150 long bed work truck always. 4.2 V6 got great MPG

[@TheNickLavender]

I drive a 2014 Tundra SR5. I used to get on average 15.4mpg on about 75% highway driving mixing with 25% city. I installed a tonneau cover on the truck, installed an AFE aftermarket air filter and now get about 17.8 or more mpg when driving. My fuel range also went up from about 325-340 miles per tank to 370-380ish. That extra 2 miles per gallon makes a difference on the highway! Also, I had a bull-bar installed on the truck and it just absolutely tanked my mpg. I removed it and it went back up.

[@1tubeleo]

Thank you, this is the type of video that is useful. I would have guessed that the topper would have saved more fuel than that, but over 200,000 miles even .1 MPG adds up. Plus they keep gear dry, locked up, and you can sleep inside them. Good video.

[@g.k.1669]

And if you get a Bed Rug they are more comfy to sleep in.

[@brianhaygood183]

Over 200,000 miles, the numbers they got would save you 60 gallons of fuel. Not enough to buy the topper, but it does mean that, if we pretend their results are significant at all, there isn't a huge reason to remove it. The weight of the topper, at 200lb, is close to 5% of the weight of the truck, so I'll bet there is a fuel penalty in stop and go traffic of a little more than this possible aero advantage. Still, numbers are so close you can basically just run whichever configuration you want.

[@fiveowaf454]

It's very hard to achieve an accurate result in any sort of mpg test. I've recently been regularly driving a 180 mile round trip to a work site and back and tracking my fuel mileage. Some days you notice heavy headwinds/tail winds that significantly alter fuel mileage, but other times conditions seem to be exactly the same yet mpg can vary by 1.5 mpg, despite this being an easy route to replicate the driving on, as there is little traffic and you can just set the cruise control. I put new Michelin tires on replacing some noisy worn BFG tires and thought the mileage had improved on day one, but it proved to be fluke conditions as the next day the mpg was back in the usual range. There are just so many variables contributing to any one run and the resultant mpg. You'd need to have some dramatic change in the vehicles fuel mileage and do several very long runs before you could definitively claim an improvement, or loss, in mpg's IME.

[@select20]

I agree with this. I drive a 2016 F150 Ecoboost V6 about 60 miles round trip. I cruise at 62mph every single trip. Some days I've gotten as high as 24mpg and others as low as 20mpg. Granted it doesn't normally vary that much, those are just the extremes, but I'd would get it does vary regularly at least 1.5mpg. I always fuel up at the same station. I have wondered though if these toppers would improve mpg. I have a hinged Tonneau cover and had been curious if it improves my mpg or not.

[@williambranham6249]

I agree but 1.5 mpg is not significant in my opinion. I suppose as truck owners we're grateful for whatever increase we get because in spite of Ford and others trying to convince us that we're getting great gas mileage, in reality nothing much has changed. The Aluminum bodies don't seem to help in spite of PR from Ford. Reducing the thickness of the finish didn't help either. I just sold my 2013 F150 3.5 Eco turbo with bed cap. 16.5 MPG. I really don't understand why so many people buy gas hogs to go to McDonalds.

[@travisjazzbo3490]

@@williambranham6249 Aluminum body doesn't help much? It is like 700 lbs difference. That is like 4 average guys. You bet that makes a difference!

[@williambranham6249]

@@travisjazzbo3490 How much?

[@travisjazzbo3490]

@@williambranham6249 700 lbs? Let's give you some perspective... Ever loaded 700 lbs into the back of a 1/2 ton pickup? It is loading it to just 30% under its max weight! you can SEE the springs lower significantly. Even if just that gave a pickup 10% better gas mileage, that is significant. I bet that is about right

[@squangan]

I have a 2009 F150 Supercrew 4x4 with the 5.4 Litre engine and 6.5 foot long box. I have both a ARE truck topper and a tonneau cover that I’ve used over the years along with sometimes driving the truck with neither of those installed. In my experience the best mpg I get by far is when the tonneau cover is installed.

[@paulforester6996]

I ran 17.something might, close to 18 mpg, in my 1995 Yukon. You have to run 200 miles to get better results. Cause I went over 200 miles for that test on the Yukon. When I had a S-10 the tailgate made a big difference, and that 4 cylinder made noticeable improvements with the topper on. It had a 8 foot bed also. This is a S-10 from the early 1980's. I don't remember the exact year though. When I check for milage, I always go further than 50 miles. One other thing, the Yukon got close to 18 mpg on I-80 where there were a lot of hills, to go over. I was surprised even, but I did try to push the gas mileage, by driving the speed limit, or a little under at times, in overdrive all the way.

[@quazaar]

I love the 4.6L. I had a 97 f150 4x4 off road super cab. It have a 5 speed manual. In Iowa, I would regularly 23-24 mpg. It did have a hard tonneau cover. I would be light on the gas pedal.

[@MidwayGuy]

Yep driving with a light foot is the best thing you can do for MPG. Sadly most people drive like they're in Formula One which just wastes fuel. Stomp on the throttle, slam the brakes. How many times do you see people accelerate into a red light? It's silly. No, you want to be smooth. Plus in a manual if you use the engine break to slow down you consume no fuel at all for that distance traveled.

[@victoryveshinojosa]

Great information. This model F-150 is the perfect size. I had a 99 F-150 with the 5.4 & the 4 wheel drive is really capable. I also managed 176K miles when I traded it in even though I've read the 5.4 can have many issues. At best I managed 17mpg on the hwy. I would def get the 4.6 with the manual if I was to buy another one.

[@quazaar]

I lent my truck to some friends. It had a slow oil leak and they didn't check it. I wasn't upset. The 5.4 could be swapped in. The auto mechanics class started the swap but never finished it. I have the truck back at home but it's been sitting for 10 years. My carpal tunnel is so bad it's difficult to work on. I have had the 5.4 in other vehicles. It's just not fuel efficient.

[@captaininsano2777]

@@quazaar i dont know why anyone would swap a 5.4 into anything. Lol 4.6 is a much better engine without the sparkplug spitting, manifold cracking,cam phaser ticking, timing chain guide eating issues of the 5.4 3 valve triton.

[@jeepjeff9131]

Two more variables to check out is driving with a Tonneau Cover and the tailgate up and with it down (no topper). Mythbusters actually did the tailgate years ago and gas mileage was better with tailgate up! Your results were no surprise but thanks for the data.

[@ebenezerwheezer2957]

@jeepjeff9131 I remember that episode of Mythbusters they actually showed that having a tonneau cover on the bed of the truck was better gas mileage than with the tailgate up or with the tailgate removed. 😮

[@mradamp125]

The science of a pick up truck bed is that the wind flows over the cab and creates a barrel roll vortex from hitting the tailgate and recirculating. This acts like a wind bubble that deflects proceeding forward wind once you gain momentum.

[@alanj7306]

I had a ‘98 Mazda B4000 before. I added a BlackMax vinyl tonneau cover (maybe weighed 20 pounds total). Gas mileage went from 17.5 up to 18 on the highway, so extra 0.5 mpg. That style cover will actually make a difference. Saved about $1 per tank (gas was only like $1.79 then) and I had it a few years, so it probably came pretty close to paying for itself. Cost about $155 directly from their website. It was great quality too and looked super sharp on that little truck.

[@br4morse7]

Thanks for mentioning this. Tonneau covers are always overlooked during the cap vs. no cap fuel economy tests.

[@charlestravis9798]

Adam & Jaime and Mythbusters did this same experiment with the tailgate Up/down gas-mileage test, and found the truck achieved better mileage with the tailgate UP.

[@bobd.]

That's because newer model pickups are designed for better MPG with the tailgate up. Think back a few years and remember the change in the top edge of the tailgate. Today and for the last 15 or so years it has been much wider or thicker. Ford did a study and found that the airstream coming down off the roof of the pickup landed right at the tailgate. By increasing the top surface area they changes the way the truck performed. There is a video on YT about it.

[@benkrom2737]

@@bobd. Has to do with the bubble affect. Air itself gives the least resistance. Drop your tailgate and air coming over cab drops down into bed and texture of bed determines wind coefficients. That's at highway speeds. Around town tailgate up can reduce fuel mileage because of less bubble affect.

[@unbalancedredneck5778]

I’d say to weigh the cap and mounting hardware. Add the same amount of weight to the truck without the topper so the weight is the same on both trips. That will isolate the aerodynamics s the variable. I would expect the results to be nearly the same as before. Cool to see a real world experiment.

[@asmith7094]

What people want to know is whether or not it helps save money on gas, not the wind coefficient

[@reinbeers5322]

Not really. A truck without the bed cap wouldn't have that extra weight, so it wouldn't have that weight in the first place.

[@InsideOfMyOwnMind]

What I wanted to know is if there is any advantage to running a cap that isn't all pigged out but has the same aero surfaces.

[@SnowingNapalm]

sorry ruined the 69 likes bit also yeah ya gotta point here i can see if the topper was made incredibly lightweight ya might not see a huge difference but more than before

[@rudygeorgiamulesandcountry1594]

Weight of the cap would approximate an that of an extra passenger.

[@deanrhodenizer938]

Thank you. Always wondered about this, appreciate your experiment.

[@11hourpower41]

I'm glad he's using the same pump through this whole test. So many people don't understand that the shutoff on each pump handle can be different up to multiple gallons.

[@jamesgeorge4874]

The "lift and beefy tires" hurt fuel mileage more than any tonneau/topper/tailgate configuration

[@mkaestn]

true!

[@markmccarty727]

The taller tires effectively lowers the overall gear ratio. The taller tires travels further every revolution , which effectively artificially lowers the gear ratio. The fact that it is equipped with a 4.6 the additional load might work the little motor harder! My truck has a 5.4 with a 5 stage tuner, I don't bother checking the milage! The taller tires probably help my fuel consumption! The lift kit may increase wind resistance, but at normal highway speeds it won't break the bank! I bought my truck to pull my camper, car trailers, and boats. I'd wager that towing a 6000lb camper it gets better economy than the 4.6.with the same load, however, I'm impressed with the milage he got with those tires on that truck. Most men will lie about 2 things, their gas mileage, and, well you know what the other thing is. They stretch the hell outta both!!

[@SylasG]

It has no significance to the test when both tests with/without topper are using the same wheels and tires. It's insignificant.

[@jamesgeorge4874]

@@SylasG no shit Sherlock, that's not the point I'm trying to make, either. "Lifted with beefy tires" never nets the same fuel economy as stock, increased drag, increased inertia to overcome, reduction on final drive ratio puts the engine out of it's max efficiency window, etc, etc.....

[@markmccarty727]

My experience is it depends on several factors, what ur doing with it makes more difference than any other factors. If you got 3.73 gears, short tires and just haul of trash and ride around, a taller tires might help.it artificiality thing it has less gear. Ud have to consider speedometer error and factor that in. Heavy trucks with small engines would probably see fuel economy suffer, while the same truck with tow package could see it improve under no additional load and on level terrain. Been there,seen it. Not Talkin 44" ground hog tires,.just slightly taller tires.

[@theprophetez1357]

I saw a similar experiment years ago. It dealt with a gang box, and showed that placing the box to the rear, against the gate, as opposed to behind the cab increased fuel mileage.

[@djg585]

But no one wants the gang box next to the tailgate.

[@theprophetez1357]

@@djg585 Only when racing.

[@richardhouvener6423]

I did a similar change on my 2014 F150 a few years ago. I was going to put a topper on it to provide lockable space for stuff as I have had on 4 other trucks, but I couldn't get one in the time frame I needed so I settled for a folding hard tonneau I could get right then. I noticed my gas mileage didn't change a whole lot from the smoother drag profile but the RPMs at any given speed went down. At 65 mph the motor speed dropped by about 250 RPMs so even though MPGs weren't a lot different, the motor was obviously working a lot more easily. Also, the truck got up to speed a bit more quickly. Either way it was a good thing and my stuff has a locking, water proof compartment. I'm happy.

[@yellowdog762jb]

Years ago I did a Before and After test drive with a new K&N cool air induction and filter kit on a 2003 4x4 Expedition with 5.4 engine. I drove the same route, the same day, about one hour apart. I reset the trip log once I was up to speed on cruise at the same landmark each time. I let the vehicle's computer tell me the average miles per gallon. My test drive was only a few miles though. My best recollection is that the brand new K&N filter system added about 1 mile per gallon on the highway while using cruise control at 70 MPH. But that was an improvement to about 18 MPG, up from 17 MPG. Around town that vehicle averaged day in/day out about 12-13 MPG with traffic and lots of stop signs in subdivisions. On subsequent vehicles I just clean my regular air filter every few months and change it yearly. Project Farm did a vid on the best air filters. I saved the top couple on Amazon and now I just buy whichever one of those is the best price at the time. I really didn't like having to clean the K&N filter and then reoiling it. I feel like I get nearly the same performance for less money and less hassle. One would think that improving the aerodynamics on your truck would have made a bigger difference. But apparently the auto makers know how to design them pretty well since they are "graded" without any special features. Still, I always heard about folks who left their tailgates down to improve their gas mileage. That's a real world test that I'd like to see.

[@brly4542]

At 18.2mpg, I think the biggest takeaway from this video is how little of a difference all the new technology makes in mpg

[@morley3810]

Agreed. Especially when towing. In my experience, it takes "x" amount of power to move "y" amount of weight. I've personally noticed surprisingly little difference between trucks, engines, gearing etc. Some differences, but as long as the truck is running correctly, very little difference. Power difference for sure, but mpg, not really.

[@theseb1979]

Weight. Modern vehicles are heavier

[@rickmcdaniel6784]

@@theseb1979 Newer F-150 have aluminum bodies, should be lighter.

[@morley3810]

@@theseb1979 weight plays more of a role in start/stop driving. Not as much effect for flat highway cruising

[@kev8839]

I like and own a few older trucks myself but with that said. The technology used in newer trucks are able to give them better safety ratings, better acceleration and higher towing ratings.

[@rts3613]

If you had less aerodynamic things in the bed, it may affect the mpg more with and without the camper shell. And, there is also the security aspect. As a contractor, I work out of a van because I don't like having thousands of dollars in tools unsecured. It only takes a few seconds for someone to steal a saw out of the bed of a pickup. You can't stop for anything without worrying, then you have to unload everything or park in a secure spot at the end of the day. For my work, its Van, Camper shell then open bed. For personal use and "cool factor" it's the reverse.

[@johnfiorentino8677]

I've put truck toppers on several of my trucks. I saw a small drop in mpg on my 2005 F350 Dually with 4x4 and 6l turbo diesel. I recently put a top on my 2021 F150 Powerboost 4x4 with 3.5l. It also seems to have gone down a fraction around town. I haven't yet taken a long highway trip. I did notice an improved ride with both trucks. My passengers note that the back seat is not as bouncy when going over pot holes and railroad track.

[@darianharris1913]

I absolutely love this kind of research.

[@stringbladestudios]

I’d love to see the test with a lighter weight Tonneau cover

[@greyestfox]

I can't say for sure but it looks like it was a Leer 100XR or 100XL and both of those are fiberglass so already presumably relatively light. I wish they'd mentioned the material to be sure- maybe they did and I missed it.

[@gilbertnadeau7181]

My personal experience is that a Tonneau definitely helps.

[@Staki6908]

Yes me too

[@jarod144]

Cap vs remove tailgate

[@sr972]

Yall have never heard of mythbusters?

[@brly4542]

In my experience tonneau and toppers don't make a huge difference. With an empty bed, pickups make a low pressure bubble in the bed, which cause the air to flow over the bed anyway

[@fj400007]

In my experience, they make no difference whatsoever , a cap actually worsened fuel consumption.

[@Dankcatvacs]

how about in the rain ?

[@fj400007]

@@Dankcatvacs Yeah, I really enjoy the advantage of the tonneau cover when going camping to keep my equipment clean, dry and offers the added protection from thieves.

[@dundonrl]

@@fj400007 Unless you need to haul large bulky cargo, a canopy (or tonneau cover) definitely has it's advantages over an open bed.

[@davidheckart639]

Aerodynamics is much about making large disturbances & vortexes into small ones. You cannot fool mother nature, and vacuum drag on the backside is just as much a problem as high pressure on the front. This is evidence that the vehicle engineers are really smart about managing air in & around the open bed.

[@badgerrrlattin35]

I've wondered about this; ya hear so many different things. I thought it might be something like this. Thanks!

[@r2bboats]

Great idea for a video. Thanks for doing it!

[@kristophertrout7328]

Without the topper you get a air vortex circling that the air flows over. If you had dropped the tailgate the mileage would drop. ( FYI, if you have a sliding back window you need a really clean bed for driving with it open. Otherwise you will be cleaning debris off the dash from it blowing in.)

[@taylorhickman84]

yeah mythbusters did a good demonstration of the benefits of the gate in the up position. I have an extended cab tacoma with camper shell, and noticed a 1+ mpg drop when I have my bike on the hitch mounted carrier.

[@chuckwyble7719]

This test would be cool in a wind tunnel where using smoke you can see how the air behaves. I saw this test that one of the auto companies did and it showed you got better mileage with the tailgate up. Because the tailgate redirected the air to fill the void behind the cab. I don't see that happening with a cap on the back. But maybe I'm missing something.... Interesting test results though.

[@Yohann67]

@@chuckwyble7719I see the same things that the wind tunnel displayed after hauling a load of mulch or topsoil. The debris swirls around, levitating sometimes a foot above the level of the side rails so I don’t doubt the study on the tailgate up. Back in the old days when I was a kid (and walked uphill in the snow barefoot both ways to school and back) we had a 1974 Chevy Custom Deluxe 2500 with a 454. My Dad being an engineer selected this truck with the anticipation of hauling a 9.5 foot camper and a boat. The truck had split rims (bias ply HD tires) and I think it was 4:11 gears. NOTHING affected the mileage. It didn’t matter if you had the camper and boat on, up hill, downhill, headwind, tailwind or any combination thereof. It got around 9 mpg LOL.

[@GaiaCarney]

Anyone who’s ever ridden in the back of an open air truck bed knows about that air vortex 😆 it was the 1980’s, us kids rode in the truck bed coming home from the swimming hole!! So stupid, in hindsight.

[@joe61499]

Doubt it

[@billgatesisanerd]

You know your viewers well, since the first time I saw 85 grade gas, I was like....wait what?? Then you immediately explained it, thanks!

[@Smokkedandslammed]

Dammit lol I lifted my 14' Tremor and was thinking about adding a topper for the mpg gains cause I thought the same thing! Thanks for the video!

[@edwardcarberry1095]

Yes ago when I had the Gass Pots. CAA 40 + yrs ago used to say canopies got 13.8% better fuel mileage. Where the bed covers got 7% better fuel mileage. If I remember the numbers the one site said that the tailgate up, tailgate down and tailgate off, the drag was 0.56, 0.57, 0.58. Since 78 I ran premium as I found going up the one hill with regular gas the car had trouble holding it's own in 4 gear. Where as with premium I could accelerate in 5th . It used to cost 10% more but got 15% better mileage. Where needing to travel with stuff in the box so a high rise canopy made the best. Also use Syn oils. Since 1986! Thank You Jim Kelly!

[@HappyCarReviews]

2004 F150 with a V8 this proves once again how RELIABLE this LEGEND really is. I sure miss my 2003 F150, it made it to almost to 300,000 Miles.

[@captaininsano2777]

My 05 has 232k runs great. 4.6 engine

[@HappyCarReviews]

@@captaininsano2777 I'm happy for you brother.👍🏼

[@LMacNeill]

My guess before finishing watching this: I'm betting worse mileage with the topper. Based upon the Mythbusters episode that showed you get better fuel-mileage with the tailgate UP rather than down -- because a vortex of air would form behind the cab, in the bed, and would essentially "lift" the air flowing over the back of the truck, almost like a roof does. In other words, with the tailgate up, the aerodynamics are almost the same as having a roof back there. So adding a topper does *NOT* increase the aerodynamic "slipperiness" (much), and with it on you now have to haul a couple hundred more pounds with very little (if any) aerodynamic benefit. Thus your fuel mileage with the topper is going to be a smidge lower. Just my guess... Now I'll watch the video and see if I'm right. Edit -- a smidge better mileage with the topper. I was wrong. :-)

[@SiFiFreak]

I remember that episode and I just don't know. It was really close. I wondered at his choice to top off as that add another variable unless he toped off untill it would take no more gas. Then without a way of detecting fuel efficiency throughout the trip. Was it just the topper or was there more traffic, did topping off put slightly different fuel in the truck. I know that the topper weights more that that could be a point in it's favor He also has the long bed version. Maybe the a different amounts of vortex are created between a long vs regular vs short bed. I think I would put a soft top on my truck as I put mostly kayaks and camping gear in the back, as well as other things that I don't need to cover but I suspect that would not be as fuel efficient as a hard top. Then I suspect that running a tonaduu is the worst for fuel, based on no vortex and no shell to make improve aerodynamics.

[@wildbill23c]

Fuel economy with the topper on my 87 Ranger is the same, didn't go up or down...that's with a 150 mile test loop that I did with and without the shell....got 24.7mpg both times. I run a topper because I don't like my tools getting wet, and the bit of weight of the topper helps with traction in the snow, being a 2 wheel drive pickup, every bit of added weight for traction is good LOL. My topper is a bare bones fiberglass Eagle brand topper, to carpet, actually doesn't have a front window in it either, just a boot that butts up against the back of the cab, if I recall the topper weighs 189 pounds.

[@markw999]

Which model truck? I used to get more than a MPG with the tailgate of my '89 Chevy down.

[@gobigrey9352]

You still have a small amount of drag in creating the vortex so with a lighter weight shell, you might see a slightly better mpg. I'm curious about different bed lengths though and how that affects the vortex along with the shell being lighter since it's smaller, also maybe with an aluminum shell since they're substantially lighter.

[@cessealbeach]

I have never seen anybody prove this until today. Thanks a Lot

[@Gman-qm6bv]

Great video sir, you answered my questions.

[@chuckgrenci6404]

The only deterrent the extra weigh would create would be in stop and go traffic. Once the mass is moving, the difference the weight would inflict would be minimal (to none). Now if there were 1000 lbs. in the bed then the extra friction from tires and the squat might effect it significantly.

[@Warrior6350]

Rolling friction definitely is a significant part of the total friction, so weight will definitely increase rolling friction significantly. I still agree with you that on highways air friction is much more important.

[@Maverick09171]

Agreed. Very few people get this concept.

[@bobuncle8704]

Great truck. Great episode. I always run a topper. Just suits the way I use my truck. What is that app you’re using? I really like the gps tracking and averaging.

[@williambranham6249]

Why do you need to know the MPG each minute. You drive it, when light goes on, you fill it up.

[@samwheelock540]

Very helpful and nicely done. Thanks!

[@dig1035]

Always wanted to know this! Thumbs up!

[@rocketj7449]

I really haven't noticed any significant gains in mpg when adding a tonneau cover. In fact, my 2019 Silverado claims 22mpg hwy, and I have never seen that number with or without a tonneau cover.

[@chrischapman276]

@cooper pason wow! Our 2011 tundra with the 5.7 gets in the 20s at that speed on flat, no major head wind other than the 70mph and cruise set. Upper 20s at that in that scenario. Shocked Nissan is so different

[@mylt1z28]

@@chrischapman276 I find that hard to believe since the EPA numbers are 20 highway and no car actually gets the EPA's rated MPG. And that 20MPG is for the single cab 2wd truck. Are you going by what the computer tells you or are you actually manually calculating out your mileage? Fuelly even says you are way over the average MPG and thats a site that reports user submitted MPG.

[@chrischapman276]

@@mylt1z28 yeah. If you hadn't replied I was going to rewrite this. We just, at this moment got home from a quick turn around from south east Arizona to The River (California border) AVERAGE was a mis- written text as we both know the total average to what I was "remembering" or thinking about was the "CURRENT MILEAGE" or "live" mileage. I paid close attention as I drove, thinking about this conversation to both the Live Mileage to the Average Total. Scenario.... I don't drive like any "SANE" person may drive slowing to the 75mph speed limit when the detector started altering me. My average speed was around 85-90, up to 100 a few times. The total fuel mileage for the entire 700 mile journey is, let me go take a look.... 14.6mpg. Mountain passes to straight Arizona desert I10 driving. However, I did pay attention to the Live mileage a lot. I was doing around 26.8 at 75mph on flat, straight, cruise set driving and got down to around 9.9 going up hill on mountains. So yeah.....I was a bit incorrect and my apologies. This is my wife's truck and I do prefer my Ram 3500 Cummins dually over this truck to drive so I only pay this kind of mind to this truck once or twice a month. 2010 tundra SR5 5.7 liter 8 banger with 140K miles and very well cared for.

[@bradgriffith4231]

The manufacturers do the mileage tests in a dyno room so there's no wind resistance or stop & go/acceleration factored in. I've never seen ANY vehicle get the stated mpg on the sticker.

[@johnmorrison8351]

My gas mileage went down slightly when I got my Leer, but it has roof bars which are likely the culprit… I love toppers on my trucks

[@TdrSld]

yes the roof rack is far more of a drag than the topper itself.

[@bobisrighturwrong]

I've put removable roof racks (Yakima) on four different vehicles I've bought new. The one I have now also has the wind deflection in front that doesn't change anything but noise. I've put them on a PU with a topper, a SUV and 2 cars. All suffered considerably lower mileage when the racks were on. I'm a mileage watcher too as most of my vehicles I keep a notebook log of every fill up. I should add that if your speeds are always low it makes little difference but at highway speeds its 1-3 mpg just with racks.

[@goombakiwi]

@@bobisrighturwrong i have a haul master rack on top of a Snugpro cap and would concur with your observation of 2-3 mpg loss.

[@joel.7372]

I seen wind tunnel tests for this kind of situations, plus tailgate up or down, or tailgate with vents in them (you don't see those anymore) and it turned out the best way / gas mileage nothing on the bed (cover tonneau or camper shell), tailgate up no vents. The reasoning is with nothing in the bed, tailgate up it creates a small vortex in the bad that helps with the overall vehicle aerodynamics.

[@blinderb853]

Fun video. I’ve put a cap on every truck that I’ve ever owned. Never had much of an impact until I put one on my midsize truck with a smaller engine. Saw some loss then.

[@brianvandy4002]

I'd assume a truck canopy only helps if you have a spoiler on the back to break the vacuum. The space immediately behind the truck ends up with a little bit of vacuum, pulling air into it. If you have an air spoiler on the tail it 'spoils' the smooth air flow and makes the air go into that vacuum space easier, thus reducing drag. Try it.

[@jamesbeaman6337]

LOL, it's amazing how we used to calculate fuel mileage back in the day without a trip odometer or GPS! But we did have to undergo the great inconvenience of writing down the mileage at the first fillup.

[@michaelkoerner4578]

It's called basic math. I still have to do it when I'm tuning a carburetor

[@BillLaBrie]

Savage barbarism!

[@robertcarmosino6563]

But , but math is racist

[@CheekyMonkey888]

I love this channel

[@marybourgeau5812]

Good Andre video.

[@russellsickler5961]

I-25 was probably a difficult ride right now, with the big update towards Longmont/Johnstown area. I also didn't realize y'all were in Colorado! I'm a little more north in Greeley! It'd be dope to meet y'all sometime.

[@7duke77]

Mythbusters did this years ago and concluded, pretty definitively, that pickups actually get better mileage with no topper and using a mesh tailgate.

[@dwaneanderson8039]

It should be noted that aerodynamic drag increases as a square of your speed. So reducing drag is less important if you are driving slower, such as in town. Also, weight becomes more of a liability in stop and go driving. So the topper may help a bit when highway driving, but will be a disadvantage in the city.

[@barlux88]

Indeed. Everything’s a compromise.

[@littlebearish]

I love the bare bones XL work trucks. And those anemic 4.6L triton engines were reliable as all get out.

[@dennishuntley7688]

Like to see a comparison between a open box verses a soft tonneau. In my RAM it dropped from 9L/100km to 8L/ 100km. A noticeable difference.

[@davemiddleditch9741]

"I cannot do it anymore scientific than this" Every nerd with a science degree: "sure you can - repeat excercise at least 10 times and calculate the average over a larger dataset"

[@brianb-p6586]

And use a fill measurement method with better repeatability, and do the test in lower-traffic conditions to allow for better consistency. But what's the point - this subject has already been studied much more thoroughly than this test, which seems to have been done to fill an otherwise idle day and provide content for another video, rather than to answer any question.

[@BrianBrazilHarmonica]

Whenever I drove long distances in my 283 small block V8 68 Chevy El Camino I used to leave the tail gate down to reduce the drag of the tailgate. It did help increase my mileage by a few miles per gallon. The mileage rating depends on the terrain you're driving on, whether it's flat or if it's a lot of steep mountain roads and not just weight and aerodynamics. Your mileage also depends on whether or not your car has 2 barrel or 4 barrel carburetor. 2 barrel type will get better mileage. If you drive at 60 or lower you get better mileage than you would at 70. Your less likely to get a speeding ticket depending on how strict the police are in your area. Driving in heavy city traffic with a lot of traffic signals is a mileage killer too. Highway driving with a steady speed about 55 to 65 will get the best results.

[@ConcoursOne]

You are incorrect. A 4barrell will get better mileage if it is driven such that the secondaries are not used.

[@bradgriffith4231]

I say bullsh!t to your statement. The air NEVER sees the tailgate & 2 barrel carbs don't get any better economy than a 4 barrel UNLESS you're driving it hard all the time. In fact, a Quadrajet carb will do better than any 2 barrel because the primary bores are so small. There is NOTHING one can do to improve the economy "by a few miles per gallon" with the same vehicle, engine & gearing.

[@paulleavitt9316]

I have a topper and a 2002 fx,4 as well and always wondered about this thanks

[@recoilrob324]

Modern trucks are very aerodynamic especially when compared to say...mid 80's. I had an 85 S-10 2.8 3.43 gear and 700R4 tranny....last year for carburetor and the motor was built with cam, Edelbrock 4bbl manifold w/390 Holley and well tuned. Putting a cab level cap (as in this video) increased the highway mpg's by 3-4 to mid 30's on a trip...but the biggest increase was in the top speed. Without the cap it struggled to hit 110 but with cap it went close to 130 if you gave it enough space. Actually out top-ended a Grand National on the way home from work in Florida one morning. He got away from the light (of course) but he'd never actually topped the car out and didn't realize they had a 124 limiter in them.....so I gradually reeled him in then drafted past and left. He was pissed. :)

[@gophermaster]

I would imagine that this is a more complex question than it first appears, based on the speed of the vehicle. For example, air dams on the bottom front of the truck actually have a negative effect on fuel economy until you get to highway speeds. It would be good to test the same thing again with the topper, but at low speeds.

[@georgewashington938]

I just finished a long trip and. On previous trips I made 80 mph my target speed. On this trip my target speed was 70 to 75 mph. Gas mileage improved from 15 to 19 mpg. This surprised me. I know trucks are not very aerodynamic, but did not think the difference would be so big (20%).

[@nathanantilla5713]

Drag increases exponentially with speed, and the powertrains on most newish vehicles are setup for peak fuel efficiency at 60mph (that's the highway speed of the CAFE standard test used to generate the window sticker numbers). Anything faster than about 65mph you're just throwing efficiency away for the sake of a shorter trip. Sometimes it's worth it, sometimes it's not.

[@samusaran7317]

@@nathanantilla5713 Dont bother educating the idiots mate. Let them learn with their wallots.

[@bradgriffith4231]

Takes a lot more HP to run 80 than 70 & the engine vacuum is quite a bit lower under the higher load requirement, thereby requiring more fuel.

[@JT-SE-OHIO]

I'm not a Ford person but the 4.6 is a great engine. I worked for Tempo campers and we used the better fuel mileage as a selling point for the cab high toppers. The VP used a 2wd Toyota pickup for the test since that was our best seller. He claimed 1.5 mpg better?? That was back in the mid 80's and for some reason I still remember the model number for the topper. C22088SRTT, That's crazy!

[@cobraskenpo2299]

Awesome video!!!

[@joel.7372]

I've seen wind tunnel tests for this kind of situations, plus tailgate up or down, or tailgate with vents in them (you don't see those anymore) and it turned out the best way / gas mileage nothing on the bed (cover tonneau or camper shell), tailgate up no vents. The reasoning is with nothing in the bed, tailgate up it creates a small vortex in the bad that helps with the overall vehicle aerodynamics.

[@godgirlsguitars]

I gained one mpg with a soft tonneau cover. I think it has something to do with the vacuum created with 3 rails going across my bed to hold the cover. The way dimples work on a golf ball I guess. Myth busters did a test like that too and dimples in a car had more mpg.

[@willb1242]

Yup this is true. I think it is also well established that the most optimal shape is a gradual slope - think the kammback of a Toyota Prius - but nobody wants a truck topper like that in practice. Maybe hypermilers (... and they'd start with a different vehicle) It makes much more of a difference to clean up under-vehicle aerodynamics. That's why most trucks now have big chin spoilers unless they have an offroad package on them; they keep air moving around the vehicle and not under, at the expense of ground clearance. Probably worth 1-2mpg alone.

[@GerardoLuna92]

Idk i've made several long trips on my truck and kept getting the same 20 mpg then after i installed a hardtop tonneau cover i made another long trip and i averaged 22 mpg.

[@user-iz3gv5vo6b]

@@willb1242 That's why most new cars have plastic coverings underneath.

[@user-iz3gv5vo6b]

@@godgirlsguitars Dimples, yes, that's why I buy used cars with lots of hail damage.

[@charliedee9276]

I worked at GM years ago doing testing on hybrid powered S-10 pickups for the USPS, we found the best mileage and aerodynamic efficiency was with only the back half of the bed covered. The wind tunnel showed the hole behind the cab allowed the air to curl around the cab, it was more aero than a full tonneau cover or no cover and the tailgate removed.

[@dmutant2635]

Some student interns at NASA/Ames Research Ctr. (2004?) conducted some tests on pickups with tonneau covers vs pickups with no cover and the tailgate down. Having the tailgate lowered, it acted like a flap, creating more drag with its increased surface area. Tonneau covers had the best results. A standard open bed, tailgate up, coming in second place. Apparently an air bubble is created with the gate up that makes for better aerodynamics. Science! Maybe some of those interns got a job at GM???

[@rustyshackleford00]

I’ve always been curious about this. Added larger drag surface area and weight seems to make it almost the same difference.

[@crazylarryjr]

There was an episode of Mythbusters where they challenged this topic and found the exact same thing, using a tonneau cover type cover (hard type). Before they actually did the driving part, they used a model truck in a water filled flow chamber, with sand in the bed, they discovered an eddy current where the water would flow over the eddy and not interfere with the tailgate. As happened here there was virtually no difference in the mileage with or without a tonneau cover. BTW they also tested tailgate up and down with the same result, so based on their findings there is almost no difference other than preference

[@91bdoug]

You watched the wrong episode, son. They said tailgate down made a significant increase in drag and decrease in fuel mileage

[@CharlesinGA]

You really need to do this over a month or two of driving (or more) in each configuration, and keep records in a spread sheet and see what you get. You could do what a couple of Lockeed-Marietta engineers did about 30 years ago when in an argument about whether you got better fuel economy and put the pickup in the wind tunnel on a frictionless floor to measure drag coefficients and get a real accurate result. Tailgate up won. The open bed with the tailgate up actually was a dead air space that acted like the bed had a tonneau cover, so the large flat area of the back of the cab, created when the tailgate was down was broken up into two smaller steps, from the roof to the bed rails to the tailgate to the bumper, more streamlined than a blunt back end. I suspect your mileage pulling a trailer would be measurably better with the topper than without.

[@henryknetsar3677]

Two out of three lab coats agree, more data is more scientific. In order to do what those Lockheed-Marietta engineers did, I would need to get a job at Lockheed-Marietta which gave me access to the wind tunnel. Question. Can I work from home? 😄

[@jwooten1951]

Obviously you have not done this yourself. Tailgate up, Tailgate down. I took my cruise control pickup four cylinder truck on 100 mile trip one way at nighttime a daily trip which I had been doing for the past year. Tailgate up, 25mpg Tailgate down 33mpg. So tail gate up I took 4 gallons per one way trip. Tailgate down it took 3 gallons that was with nothing in the bed of the truck. The tailgate up acted like a big air damn costing me a gallon per hundred miles. The scenario described by you is what the Saturday morning PBS Radio, mechanic brothers from Boston like to use as an excuse, Frick & Frak

[@CharlesinGA]

@@jwooten1951 Actually I did, about the time the Atlanta Journal article about the Lockheed engineers test came out I had a Jeep Comanche pickup with an open bed and it was largely driven to work, 50 miles each way, mostly interstate, and I drove it for a couple of weeks with the tailgate down (normally it stayed up) and consistently got worse mileage with the tailgate down over the two weeks, not a lot of difference, about a mile to mile and a half per gallon. I always fill the tank and it was easy to track the comsumption accurately.

[@ljefferies2012]

I never really noticed a difference when adding just a camper shell to two different trucks. I did noticeably lose at least 1 mpg from adding roof rack crossbars on to each though.

[@mikegillaspy1721]

My buddy has a jeep he put rack on. Lost 2 mpg. Made it noisy too

[@bradgriffith4231]

Anything that creates air flow disruption will reduce mpg. Even removing the front air dam or adding a lift kit will hurt economy.

[@scottw5253]

LOVE IT! Knowing the answer .02 of a second after seeing the video title, makes watching a test vehicle so perfectly illsuited for use as a test vehicle in a, "scientific test," all the more humorous and fun to watch. Cheers. (Why am I left with the impression that this one was done, to some degree, begrudgingly? 😉)

[@stanb990]

1996 F150 300I automatical 14.8 mpg Added a fiberglass topper and diy drawe system made from 3/4 plywood and loaded with tool's 17.1mpg 2005 Ranger 24 mpg Added heavy commercial topper/tonneau cover. With diy 3/4 plywood rack system 27.7 mpg

[@MichaelGalletly]

Well, the good news is that the topper didn't cost you anything, efficiency-wise.

[@RedWingsninetyone]

I imagine a lot of factors come into play. I wouldn't mind seeing this test again without an 8' bed as well.

[@TheChippymase]

Who would of thought a video comparing the milage with or without a topper would bring almost half million views!

[@johnmcdougald1238]

Exactly the same results I've gotten with my truck for the last 13 years. I drive a 2008 Dodge Ram Megacab 1500 4x4, that I special ordered. 5.7L Hemi, 545 RFE Transmission and a few options, no lift, factory size tires, and even though it's a 1500, it sits on a 2500 chassis, minus 1 rear leaf spring. From my 1st fill up, I averaged 8mpg. As the engine wore in, it improved to between 10-11mpg in combined driving. I've tried tuners, Cold Air Intakes, different brands of gas, different octanes of gas, and different blends of gas up to Ethanol Free, and I also own a Leer Elevated topper instead of the roof line topper . I ran my own test, running 10 full tank fills of all the area gas stations. I've down this twice over the last 10 or so years, 10 tanks each with the topper and 10 tanks each without the topper and my MPGs have always remained around 10-11mpg.

[@bradgriffith4231]

Honesty prevails. There's very little one can do to improve the mpg in any vehicle. Tuners & the other performance "enhancements" usually hurt mileage, except with diesels.

[@WindsorLiaw]

What app were you using on your phone to keep track of speed?

[@xziang]

I am wondering if they were using onX off road since they are partnering with them lately. But was curious myself.

[@joshharman3611]

I was wondering as well.

[@joshharman3611]

Found it. Altimeter Ler

[@rodwspoon304]

@@joshharman3611 thank you bro 😎

[@BryanH2700]

I think it would be interesting to see if this would make a difference while towing some type of high profile trailer like an enclosed or camper trailer.

[@wildbill23c]

To a slight degree yes....but it wouldn't be a huge gain in fuel economy. A channel I'm subscribed to did something a little different but has a Jeep that he tows a trailer with, and installed a spoiler on the back of the Jeep to see if it would improve his fuel economy...it did a little bit....here's a link if you are interested in seeing what he came up with.....kzbin.info/www/bejne/b5PZkniPe7l-iZY

[@juliohur4001]

Makes sense to me. The topper added the weight of about another person in the truck. Without the topper and the tailgate up seems to catch the airflow off the top of the cab, creating a drag. I have seen people drive with the tailgate down to reduce drag. Just a thought.

[@markmccarty9793]

Most people don't actually know what their actual milage is on a regular basis. I've gripped bout the milage on my 05 FX4. But, once I checked it a few times I realized I drive alot more than I thought! It does a really good job towing, and it has a tuner on it to help.

[@sleim754]

What program did you use for the altimeter and distance?

[@toobalicious]

I’d like to know this as well.

[@michaeloltman657]

I would like to know also.

[@krphysio]

Yes. Which app is this

[@Diamondboarder]

Yea please let us know!

[@kurtm2862]

I would like to know as well!

[@quicktoevil]

No topper here; good ones are expensive, rear visibility suffers, loading and unloading is awkward or impossible and two man job to remove and replace. I used one for camping but all other times I hated it. MPG saved or lost wouldn't sway me one bit to get another.

[@JimSpence]

100% agree. Well said.

[@SimplyCarReviews]

Yes I had one on my Tacoma . Now on my Gladiator I have a bestop soft topper that folds down to me best of both worlds.

[@philtripe]

i have and extra tall, no window cap for work so i can keep my tools secure and i have carried 500 pounds of plywood on top of it... of course its not for everybody but its a lot easier to get stuff in and out of the taller caps... those low ones are nearly useless

[@BIKEMAN21]

Would be good for sleeping if you are camping. I would get one but mainly for the way it makes the truck look nicer. they are pricey though.

[@bloodbushcraft2467]

Lol I've got a tall one I bought used for 75 bucks. I love being able to keep things dry. It was great on my 8 foot bed but now I have it on a standard bed for it extends about a foot over. Actually gives me more storage.

[@user-iy6de7qi1r]

I had an 84 C-15 chevy pickup in the nineties, and got practically the exact same fuel mileage over three years as you came up with, driving about fifty thousand miles before selling that truck. I also ran a Ford half ton with pretty much the exact same outcome right after the Chevy. I'm currently running a 2022 Jeep with a V-6 and getting a couple miles to the gallon better with less weight and about the same cross-sectional area for wind resistance.

[@bradgriffith4231]

Weight & smaller, fewer cylinder engine. 90% of the parasitic drag in an engine is the piston rings sweeping the cylinder. Fewer cylinders usually get better economy, Harleys get GR8 economy compared to 4 or 6 cylinder bikes with the same displacement

[@user-iy6de7qi1r]

I never really thought about that aspect but it makes sense!@@bradgriffith4231

[@robertboykin1828]

Thank you, I was wondering.