Shocking MPG Impact of Driving 10 MPH Over the Speed Limit. Mind blowing results!!!

[@Pickuptrucktalk]

Nice truck!

[@GearsGadgets]

@@Pickuptrucktalk thanks. A lot of my decision came down to some of your commentary on the 3.0 duramax.

[@Pickuptrucktalk]

@@GearsGadgets it is a pretty amazing powertrain once you get over the apprehension of owning a diesel.

[@Sidharth-ci8sk]

​@@GearsGadgets regardless of your political affiliation you must condemn attack on TRUMP

[@1diggers1]

@@Sidharth-ci8sk Well that was random.

[@RustySax1949]

@@GearsGadgets - Dan, I've got an "old" 2003 VW Jetta wagon, 5-spd manual TDI diesel, the last year of production with a mechanical injection pump (newer models are electronic FI.) With a completely stock drive train at almost 309,000 miles, in 5th gear: 2200 rpm = 62mph/100kph 2400 rpm = 67mph/108kph 2600 rpm = 72mph/116kph When I make a run to my cousin's place in Yakima, WA from my place in Spokane, WA (a little over 200 miles), it takes 3.2 hrs at 62mph, or 2.7 hrs at 72mph, a difference of about 30 minutes. However, if I drive 72mph, I get 38mpg, but when I drive 62mph, I get 53mpg, a difference of 15mpg running 10mph faster! So I normally compromise and run at 2400 on the cruise control, which takes just a smidgen under 3 hours for the trip, getting an average of 45mpg and I'm happy with that.

[@DerHossMeister]

Aerodynamic drag......physics baby! Saving gas was why we settled on 55mph as a national speed limit back in the 70's

[@doughaven-rf8id]

Not to mention the roads were designed for 55 and now traffic is traveling at 80 mph on the same road. Today people are so amped up and stressed for time. If the posted speed was set at 90 they would travel at 95. Beer is good and people are crazy. lol

[@randyfender6122]

​@@doughaven-rf8idsorry, but the interstate system was designed for 75mph in 1950's cars with drum brakes. They never saw 55mph limits till the 70's gas crunch.

[@doughaven-rf8id]

@@randyfender6122Sorry, you are mostly incorrect. The first Interstate highway began in 1956 and the system was built throughout the next 4 decades. The Interstate Highway System was declared compete in 1992 when most cars had disc brakes. Further more, I wasn’t necessarily talking about just interstate highways. It still doesn’t change the fact that many people lack the attentiveness and skills to be driving a vehicle at 85 mph +.

[@randyfender6122]

@@doughaven-rf8id Most of the major interstates were mostly completed in the 70's .As for skills, I blame that on lax licensing, the switch to auto transmissions, and cell phones. I think any accident caused by texting and driving should be an automatic suspension, and texting and driving infraction fines should be a percentage of annual income, since a couple hundred dollars to someone barely scraping by is a big incentive, but to someone making $500k or more is nothing. Actually all traffic fines should be that way. Call it equity.

[@100pyatt]

Bingo ! From 60mph up, aerodynamic drag dramatically increases with every MPH higher

[@shenandoahmaxey6179]

I bought a 24 chevy crew cab 4x4 z71 with 3.0 liter diesel two months ago. Tested it on 385 mile trip down and back to Indiana 2 times in the first month staying at max of 65 mph each time and averaged 34 & 35 mpg. These 3.0 liter Duramax diesel engine in these trucks get unbelievable mileage.

[@xcrazelr]

OTR truck driver here us semis do about 68 if speed limits allow. If you try doing 62 mph you may see a drastic difference in your mpg savings. Main thing is stay low in the power band and high enough to be in your highest gear. You can save your self so much money by doing this.

[@schreilavoge]

I drive about the speed limit. No more than five over and I will say the thing I noticed most when I started doing this is it's just a lot more chill. Rarely have to pass anyone or change lanes just cruise. When you start passing people and make maneuvers is when people start acting like bitches just to fk with you. My trucks rolling at 8k lbs. Im unfazed by anyone around me.

[@roundstone2020]

I want to be your friend.

[@OrngRubberDucky]

So true, my wife calls me a grandpa driver, but I get way less upset then she does when driving. Plus I keep track of some people that pass me and I'll notice I'm only a few vehicles back from them on the off ramp. People need to stress out less.

[@ardyarco5221]

I have a 23 Suburban 3.0 duramax, we just moved from Indianapolis to Minneapolis Almost to 600 miles. I was driving a uhaul truck with a trailer behind it 60 to 65 mph the hole time. The Suburban ran right behind me with my wife driving. It was loaded 1 adult 4 kids and tons of boxes. Amazing we got over 40 mpg Still had over 3/8 of a tank left when we arrived. Pretty amazing.

[@100pyatt]

Diesels rule !! ♥️♥️💪

[@dana.6695]

I found that the difference in fuel efficiency between 70 and 75 is quite substantial. With any truck the lack of aerodynamics really kills your mileage at higher speeds.

[@GearsGadgets]

True

[@ronaldstephens5695]

Everybody needs to slow down, you only get there about 15 minutes quicker, look at the money you could save driving the speed limit.

[@Kil7witch84]

@@ronaldstephens5695 - My time is well worth the cost. It's a steal of a deal.

[@huntz7847]

These results are consistent with tests that others have conducted. I am completely sold on this truck. I fucking need one!

[@GearsGadgets]

I haven't had the truck long enough to recommend it BUT I will say my early results all around with MPG, comfort, and performance has me leaning toward saying this is the nicest truck all round that I have ever owned / driven.

[@waylinnelson]

Ignore the dumb comments. It’s just your own experience. No idea why people always gotta blast KZbin videos in the comments. You make great videos that are always informative. Thanks for another great video!

[@GearsGadgets]

Thanks I really appreciate that.

[@KhaoticKalm]

I never understand the people that have to put someone down to feel better about themselves. There seems to be a lot of them though.

[@jamesjohns4464]

I love going the speed limit or less. Put it in the right lane and the stress melts away. No pressure or anxiety at all. But I do drive a 3500 gasser and get 16.9 at 70.

[@GearsGadgets]

Totally fair. As long as you stick to the right side of the highway.

[@100pyatt]

AGREED !! 58mph and watch the sheetshow of clowns in a sheer PANIC to be first off the exit 💯🤡💯

[@robertroth1042]

You’re a human being when I don’t make mistakes anymore I’ll be long gone 😊 Thanks for doing this because I’m contemplating on buying one of these trucks !

[@leshunter4409]

A very good demonstration of the fact efficiency is directly related to engine rpm. That is why all manufacturers are using transmissions with more and more gears. Small displacement diesel vehicles are and have always been the answer. EV's are absolutely idiotic. The Europeans have known this for decades.

[@brianthollaug7111]

Efficiency is directly related to speed. It's called wind resistance and frictional loss. The advantage of low RPM is reduced internal friction and improved thermal efficiency. EVs are orders of magnitude more thermally efficient than internal combustion engines meaning the energy you buy is used to make your car go instead of being converted to heat which is rejected through the radiator or blown out the exhaust pipe. And they offer the opportunity to operate on renewable sources of energy. The Europeans have encouraged small displacement engines (higher RPM) for decades. They are also well ahead of the US converting to EVs.

[@bw3506]

I've always thought diesel electric was the way to go. Especially on heavier vehicles.

[@RustySax1949]

@@brianthollaug7111 - Are you aware that Teslas are so energy efficient that Hertz Corp sold off over 20,000 of the Teslas in their national fleet? Many of which had under 15,000 miles on them, which is about 1/2 the normal mileage for rental car fleet turn over mileage. If they're so efficient, why were they sold off?

[@catbird1759]

I have an old school 2002 F350 with a 7.3, if I stay at the 2000 RPM range, I get 3-4 MPG more than my 5 above the posted speed when pulling my 5th wheel. Driving conservative can help the wallet no matter what we drive. Great video!

[@Leeshlongington]

I have a 2000 F-3kitty not entirely sure as far as gear ratio, as it was my grandfather’s truck but that thing can’t do 70 at 2k rpm. Hands down my favorite diesel and noise making machine!

[@100pyatt]

Probably 3.73s , these were available in 3.55, 3.73 and 4.10 in that model the 450 and 550 truck had available 4.88 and insane 5.30 gasser ratios. The 3.55s got the best mileage at 1600rpm. I have a Friend that swapped in custom 3.23s and was getting 30mpg from his first Gen 7.3 PSD 2wd

[@jameseroh6544]

As a long distance communter in a major West coast city. I work a 12 hour shift, 3 days one week, 4 days the next week. So I camp out in my vehicle during those work days. Since my work commute is 360 miles, I get to test mileage every trip. One of my vehicles is a '16 Ram 1500 Quadcab Ecodiesel 3.92 ratio. Driving 70mph the mpg was 33. Driving 52mph down 2 lane highway, 48-52mpg was common. Unfortunately, after a few emissions software updates, mpg is back to the EPA sticker of 25mpg at 70mph. By the way, use Hot Shots Secret EDT every tank of fuel. That keeps your DPF, EGR, and SCR way cleaner. My truck is now a backup vehicle with 179k miles. My gas '20 Dodge Durango GT 4wd 3.6L actually gets better fuel economy of 26mpg at 70mph. But up to 37mpg at 52mph on the 2 lane highway. Keep in mind that the open highway speed limit before the early 1950's. Was 45mph, or less. The old Grapevine/Ridgeroute highway, now known as I-5, was a 15mph speed limit. And with improvements, the speed limit was raised to 25mph. With todays double overdrive transmissions. We get to enjoy power and fuel economy. Compared to any vehicle from the 50's, 60's, 70's or 80's.

[@TinMan0555]

I have always driven for the best mpg……I quit hurrying many years ago. My truck (1/2 ton, 4x4, gasser) does not like 70+ mph. At 65 mph I can get 21-22 mpg. Much over that and I’m down 3-4 mpg. I have done the max (85 mph) on the toll road around Austin. That 25 mile run pulled the mpg down to 14mpg. I always stay in the right or middle lanes. To all the folks that wanna go faster, go around. Hugging my tailgate only makes me ease off the gas. If you decide to reduce your reaction time by following too close, I’m gonna slow down a bit just to give you more reaction time. The closer you get, the slower I go. 🤨😊

[@GrdDog]

I have been driving Over The Road (OTR) for 30 years last 20 years as an Owner Operator with 3 freightliners running OTR. There is a reason why the company drivers get "fuel bonuses" including the two I have driving for me, fuel savings = profit plain and simple. My freightliners consistently pull in over 9 m.p.g because of the speed control the driver uses; especially using the cruise control, a critical miss step many make. The trucks can run a lot faster if the driver chooses too; just means the driver will be loosing money and putting more wear and tear on the truck. If you want to burn through money by all means push that accelerator to the floor or just throw the cash in a fire, same waste will happen. Burn the engine because of the driving habits and the driver will be without a truck until fixed at minimum, fired at the max.

[@madweazl]

Maybe trucks are different but I've never had a car or light truck ever get better mileage using cruise over not using it and just maintaining a constant speed. Definitely a huge difference towing our 5er (16.5k pounds) at 75 vs 60 mph though ('24 GMC 3500 w/Duramax). We towed from VA to AZ across the norther route (largely I90/I80) where the speed limits were high and averaged about 8.4 running around 75mph but hit 11 once we got to CA and were driving at about 60mph. It seemed so agonizingly slow lol.

[@GrdDog]

@@madweazl The old semi's and personal vehicle I agree with you; the cruise just held the constant speed. The new cruise control is linked to the computer; that does a lot of tech stuff to help a driver of the vehicle obtain optimum performance. In a commercial vehicle (Class A) I know that the upgraded computers in a 2022 and 2023 Frieghtshakers have a much different system than a 2016 and it shows. If a person is educated enough to use the system (kind a like a Linux O.S. for personal computers); the same can be said about the personal side of the vehicles. Most that buy a brand new vehicle or a vehicle that is newer (to me over 2020) has a lot of new functions that dealers do not discuss with a buyer (KZbin if your best friend for that) I just went through that orientation myself for both kind of vehicles.

[@bdjm8595]

I have a 03 Dodge Cummins and can vouch for this kind of result. I ALWAYS get significantly better mileage on secondary highways were the speed limit is lower vs the freeway !!

[@katanamaki9015]

I have an 04 Ram/Cummins dually and I agree with your findings. I too get much better fuel economy on secondary hiways with my truck than I do on a freeway like the Coquihalla hiway!

[@2DangerousDan]

I have a 03 Ram 3500 5.9 Cummins and I averaged 27.5 going from Missouri to Idaho to California running 5-8 mph over the posted speed limit. IF I took a hit it was worth it. I did have a 100hp chip installed at the time that I have found increases my cruising mileage by 5mpg though.

[@bobthebrowsersstuff704]

With a trailer that 10 MPH makes a HUGE difference! I too can't stand going slow. However over 1000s of miles with trailer driving on the slower side make a big difference on budget.

[@GearsGadgets]

@@bobthebrowsersstuff704 oh no doubt. With trailer it makes all the sense in the world not only for mpg but for safety too.

[@patrickday4206]

Yes my truck with a cargo trailer gets horrible gas mileage unless I go slow and my cruise stopped working so driving slow is difficult

[@doughaven-rf8id]

@@patrickday4206 Anything extending past the body makes a difference. Back in the late 70s & early 80's everyone was installing visors, running boards and big mud flaps . Extra surface area of these accessories was like half of a plywood sheet and they couldn't figure out why their mpg dropped off.

[@cs2884]

As I've gotten older, 30 now, I only drive slightly above speed limit by 5km. I know I'll never get pulled over heading to work. I find it's safer to go speed limit and youre maybe saving a total of 3 minutes to most destinations by speeding and is more dangerous in terms of reaction time and no worries about cops around the bend.

[@GearsGadgets]

To each their own

[@garysarratt1]

I typically go 7 over.

[@garysarratt1]

…I mean I would if I was a speeder 😌

[@GettingAGrip208]

I used the be the same as the guy in the video, I’ve witnessed some things and had a few close calls and now I set cruise control at 5ish over speed limit and just cruise. MPGs are great, I can relax more during my drive and increase safety by a large margin by being able to slow down quicker and react to incidents in a MUCH safer manner. Also arrival time is barely different over my 30 mile drive, I’m always early anyways so getting there 3 minutes earlier is literally just time wasted. However on 12+ hour drives I push slightly faster, because the return of time is increased greatly over that distance.

[@justinhair6173]

I have a 21 Silverado RST 3.0 and had to take a work trip to New Jersey the other week set cruise the whole way at 62 in the 55 zones and 68 in the 65 zones and I got 37 mpg, I was mind blown, the trip was 202 miles and the fuel gauge didn’t even move

[@GearsGadgets]

Yeah it is insane.

[@garysarratt1]

They pump your fuel for you there, you ripped off some poor starving college kid 🤣

[@jameskiyabu6541]

6.2 gas in a 2023 Sierra Denali 4wd pu. 14 to 16 mpg at 85 to 90 with lots of idling .

[@ozzielee8778]

I’m one of those that more less drives the speed limit, but no I don’t ride the left lane. I’ll take this opportunity to comment on those ride my azz, honk at me, pass me and flip me off. I typically exceed the EPA ratings for instance on a recent 250 mile trip I got 25.9 mpg on my 2.7 Ford rated at 23. This is driving around 70mph. For what it’s worth technically the speed limit is the “max” speed, so if someone say is driving 62 or 63 in a 65 they’re not the problem if you want to drive 70. If you want to drive faster than the limit I don’t have a problem with that but don’t get mad at me for going the limit or slightly lower.

[@heroofharo]

@@ozzielee8778 just allow people to pass. It is in fact called the high speed lane or the passing lane in most states.

[@mpccenturion]

Been running diesel, and turbo diesel for 30 yrs . As you increase speed, the resistance force is squared. That is why the mpg hit is so high. However- 50 mph on secondary roads, I could get 58mpg. The current engine transmissions are set up to give you those numbers. Change your rear end/front hubs for taller gears. and you get much better mpg.

[@victor_beltran]

On these 3.0 duramax, Mpgs is one thing. Reliability is another.

[@victor_beltran]

@@ForgettingTheFear you gonna be laughing all the way to the dealership when it always there

[@victor_beltran]

@@ForgettingTheFear broke? You think driving an 80k truck is rich haha grow up kid

[@Mason-fv1zl]

@@victor_beltran looks like somebody’s butt hurt over a comment sad.

[@victor_beltran]

@@Mason-fv1zl says the one who took it to heart

[@Mason-fv1zl]

@@victor_beltran bud what?……… who dropped you on your head

[@cowelk]

I, too, live in the Phoenix area. I typically drive about 5 mph over the speed limit. I get passed by numerous vehicles going 10 to 15 mph faster than me. So, I drive in the right or middle lane. It is a fast driving town. The biggest danger in getting rear ended is if someone is going slower and driving in the left lane. Excellent video.

[@robm3357]

Driving slow in the left lane is an American way of life, isn’t it ? I’m Canadian and for the most part have signs that say keep right except to pass. But I noticed in the states holding up traffic while driving in the left lane seems to be a god given right.

[@papap.8006]

@@robm3357 That a fact! 100% correct. ✅

[@GearsGadgets]

I think it is just the low bar to achieve the status of "I got my drivers license" but thats just my opinion. Those of us who know to move over had a father figure who from the passenger seat said some form of "You're being a dick, move over"

[@yesidrive]

Forget save time drive with your brights and fog lights on fix everything

[@Leeshlongington]

Midwest here and if you aren’t at least 5 over you are wrong even in the right lane , I drive semi truck and I can’t tell you how many people in Illinois can’t fucking drive, sure they drive fast but they also can’t follow literally any law.

[@paule4696]

There are a lot of them however.....I live in Michigan 30 miles from the Port Huron/Sarnia border. I see a LOT of Canadian drivers, especially trucks, driving slow in the left lane. So many in fact that I assumed that the rule in Canada might be backwards.

[@axcs0119]

I did a similar test when I bought my Mazda 3 back in 2013. I drove from Maryland to Oklahoma with the flow of traffic. On the way back I did 65 no mater if the limit was higher. Trip was 1340 miles each way. At 65 I managed a 18 gal saving per mile.

[@333jfish]

Great video, I lived in Phx for 25 years and can confirm if you don't go at least 10 over the speed limit, you will get run over. I have a 24' Denali 3/4 ton. best milage I have gotten so far is 27.7 MPG. 55 MPH for like 40 miles on a two lane mountain road. My truck hates city driving though 11-13 MPG at most either empty or towing my trailer. Loves the HWY and get 18 MPG towing my trailer.

[@ljjones2464]

Before building my 21 x31 for overlanding 35’s, 4” lift, additional armor… my average was 31mpg driving like you did in this video. Now it’s closer to 26mpg.

[@firefighter4443]

I drive 30,000+ miles per year. Straight speed limit for me. Right lane the whole way. Fuel economy is awesome, never get stuck behind anyone. I haven’t been rear ended yet, and I’m driving a Black 2009 Hyundai Elantra. I’ve heard many claim you’ll get rear ended going speed limit, I say show me ANY proof it’s EVER happened. I’ll wait.

[@GearsGadgets]

@@firefighter4443 Proof: kzbin.info/www/bejne/iKPcpmtrd9l0gq8si=QRSO22hyqpnyr9Cc

[@GearsGadgets]

@@firefighter4443 so while it’s nice that you’ve kept your bumper clean, it’s quite possible you’ve been the cause of others getting dinged up, or worse hurt. The world is bigger than just the inside of your car and your actions directly impact others.

[@a9ball1]

Yeah, your right. We shouldn't obey any laws just because someone else has broken them. Makes sense to me. Murder someone, why not other people have done it. You can't pick and choose which laws you will obey. That's why it's called a law not a suggestion.

[@truetexan7755]

​@@GearsGadgets So,,, are you advocating that all pf us speed as fast as we can to avoid getting rear ended or causing others to get into accidents by reckless driving..... Then why don't we all drive at say, 100 mph or 185 mph , maybe 200 mph .,,,, you know , just to make it safer so others don't have to go around us . Hell,, let's just strap jet engines to our cars and get up to 750 mph . 😅

[@randyfender6122]

​@@GearsGadgetsI'll also point out that it's a FACT, verified by much testing and data from the NTASA (?) that the safest speed to drive is the 85th percentile. What's that? It's the average speed that 85% of traffic is driving on any given road. Typically 5-10 mph over the limit.

[@Mark-trosusa]

I have a 2023 Sierra 1500 Denali with the LZ0. I have touched 33 MPG but that's the exception. We just got back from a 800 mile road trip from sea level to over 4000'. I kept the cruise at 10 over so 70 to 80 for almost the whole trip. Avg. was 25.4 MPG.

[@rsbreeze]

With my 24 2500HD ZR2 Bison Duramax, the best mpg is around 68-70 mph at about 18 mpg. That's 9000 lbs, sitting 7 feet tall, rolling on 35s, with a massive open front grill. Running 75 mph, I can still get 16.5 mpg. Not too bad!

[@REF49]

I got a similar result in my 2024 F150 5.0. Wind, inclines, fuel, conditions and engine all make a difference but 65mph saves fuel consumption as expected.

[@jeffreyuth6362]

I also have 2024 GMC Sierra 1500 AT4 (CarbonPro) and I drove from Holbrook to Sierra Vista AZ, 337 miles, and it only took half a tank. I average above 30 mpg consistently on the highway and I go about 5 over the posted speed limit. I have just under 5k miles on the truck. It has gotten better the more miles the engine gets.

[@cragar]

I get about 33 MPG in my 2014 diesel (3.0) 5-series in mixed driving. I don't drive conservatively. I've driven from MA to NC and got +37 MPG going 80+ MPH. All these newer small diesel engines (3.0 /2.8) are very similar in design.

[@GearsGadgets]

Crazy efficient.

[@formerice]

Found about the same thing with my Ram Ecodiesel. 32 mpg at 65 and 24 at 75 mph. I live in Maine , though.

[@chiensibi1231409]

This truck with the power on board of f150 is my dream truck.

[@ralphscholz9533]

Yes, indeed. I know from personal experience that extra 10 MPH gets really expensive at the pump, real fast.

[@petewalter7462]

I have driven in Phoenix, this was so funny. You are a tough guy.

[@thesandman775]

Absolutely consistent with what I've seen with mine as well. It's a huge drop off once you crest about 70mph. Between about 45 and 70, the mileage numbers are hard to believe with a full size pickup truck.

[@billdouglas6561]

These newer trucks are HUGE !!! The front area compared to the older is massive !! So therefor more air is being pushed the faster you go . Should have done a faster test also .

[@jamesschneider3329]

Late to the comments, but nice video. This result isn't just a diesel thing. I experienced the same phenomenon with an '06 Hemi Charger I used to own. It is really down to the aero of your particular vehicle, combined with running it in it's most efficient state. Open road driving at 65 for me resulted in economy matching the EPA rating. 75 mph under the same condition never let the engine go into MDS mode so economy was about 5 mpg less- I didn't care for that. I could bust 30 mpg in open road driving. but had to be going 55 mph to keep the engine in 4 cylinder mode. The one time I got the best economy (35+) was strangely enough when I was going the fastest, about 80-85. The engine maintained 4 cylinder mode because I was in heavy freeway traffic and I simply kept pace. I believe the volume of traffic created a tunnel of air that moved along with the cars and created an effect as though there was no wind resistance. This situation was nerve-wracking for me because you never know when traffic is going to suddenly slow down for whatever reason along with rolling terrain that prevented seeing very far down the highway.

[@jbjlock26]

Not surprised at those results! As for the comment about the effects of towing on DEF consumption, my results were that the first tow with only about 1000 miles on it, the DEF consumption was totally wonky! Seemed like normal, then suddenly I'm getting low DEF warnings! Over the long term, this never happened again. Yes it's probably higher than running empty, but I did a 6,000 mile+ towing and I just topped off with DEF at about every other fill at truck stops, and never saw extreme consumption. I have since traded that 1500 on a 2500HD Duramax 6.6. Talk about a brick going down the road...with enough power to move a house...my best 50 mile mpg is now at 21.8! Real world it's doing better than 15 most of the time, and probably averaging closer to 17.

[@GearsGadgets]

That's great info. Yeah the 2500 is a significantly larger brick.

[@garysarratt1]

I’ve just passed 1700 miles on a not-quite full def tank with my 6.6 dm. That’s about standard for me; it’s roughly 1 per 2.5 tanks of fuel (around 7-800 miles) when towing. I wonder if tow/haul mode accelerates it?

[@robm3357]

I did a similar test and was blown away. I was running country back roads at 50 mph and my Colorado 2.8 diesel got 10 more mpg than it does on the highway. 42mpg. Our gallon is a bit bigger than your but a small diesel engine can get amazing mpg. Love my Colorado diesel.

[@ttwan0081]

i have a Canyon with the same 2.8 its absolutely amazing the mpg is crazy

[@robm3357]

@@ttwan0081 I don’t understand why we don’t get massive credit for using less fuel and getting amazing fuel mileage. And why GM isn’t pushing these diesels to help meet the MPG requirements.

[@Propnut48]

I have a 2019 Ram 2500 HD with a 6.7l diesel and did a test (by accident) by leaving my truck in 5th gear instead of drive one day. I routinely drop it into 4th or 5th because of the winding roads where I live and one day forgot to kick it back to Drive. I am mindful of the mpg and saw it was getting 28 mpg instead of the usual 15-17. I drove on a flat road at 60 mph and held the throttle at a set rpm and kicked it to 6th gear … it dropped down 10 mpg instantly. While holding the throttle steady I dropped it back into 5th and it immediately went up by 10-12 mpg. I was getting on average 13-15 but now it is 19-24. On long distances it in the 24-27 mpg average now. So 5th from now on it is!!!

[@rogerf7265]

I have a 2020 Mitsubishi Mirage for my commute and the difference between running 70 mph and 80 mph is pretty significant. At 70 it gets 45-46 mpg and at 80 it gets 38-40 depending on the terrain. Running 55 on secondary roads it has gotten a high of 51 mpg. These days I just stay in the right lane and go the speed limit because around here it doesn't matter how fast you are going there is always some idiot that wants to pass you.

[@AlanSanderson-u4t]

I have a Grand Cherokee with the 3 liter EcoDiesel. On I84 through southern Idaho the speed limit is 80 cars, 70 trucks. I got 32mpg at 75, 26mpg at 80. Range at 80 is 637 miles, at 75 it is 784 miles, so it also cuts down on fuel stops. With the radar cruise control at maximum following distance behind a semi, it gets 44mpg at 70.

[@andremorse9282]

I did 54 mpg in my Nissan Rogue, at 55 miles an hour. With everything just right, tire inflation I was blown out of the water with 20 mile hour increase I went down to around 34 to 36 mpg.

[@eriklindholm6577]

I own one of these and love the mpg. One heads up. When you tow with it, the diesel exhaust fluid goes faster.

[@freebehindbars8654]

*Delete

[@GearsGadgets]

That’s good to know, @freebehindbars8654 I will not be deleting. The DEF systems of today are not the DEF systems of 2014. Deleting would cause WAY more problems when it comes to warranty for very little payback.

[@robm3357]

When you tow you use more fuel and using more fuel means your producing more NOX. More NOX means you need more DEF to counter the higher NOX.

[@garysarratt1]

Oh heck yes 😭

[@scanadaze]

My 2020 F150 3.5l Ecoboost. If I just do hwy. 4 over the speed limit. Around 20 mpg average. 36-gallon gas tank. That's 724 mile range. Best mpg I got was 22.7. Nice GMC.

[@GearsGadgets]

Thanks.

[@cjdaniel2010]

I believe the 33 mpg. I took a 180 mile trip last week in my new AT4 just like yours and got 24 mpg at 75-80 mph. I did a 30 mile trip averaging 60 and got 29 mpg so 30+ is very doable. I am ready to tow my open car trailer and see how it does towing 5500-6000 lbs. Great video, cool to see someone with same truck doing these tests and excited to see what mods you do to truck.

[@GearsGadgets]

Thanks! I would love to hear how that towing MPG comes back

[@byronhaley1566]

I got pulled over for speeding in Oklahoma City for "going with the flow of traffic" and 10 over the speed limit. Every city is different. And repeat the experiment with different gas stations. I know that every pump is supposed to be "certified" accurate, but I found some stations are different. I was suspicious of a certain station because the fuel mileage was always extra low, then one time the gas pump said I put in more fuel than the car was capable of holding by 2 gallons on a 13gallon tank!

[@mendiesel7932]

I routinely got over 30 on backroads averaging this speed in my 2020.. That said at 80 on the highway I’d get no less than 27.. Either way, that truck is sweet.

[@EnthusiastCarHangar]

Interesting. I will do the same test in my diesel F-150 and see what I get.

[@bret9741]

That is interesting. I have an 07 F-150 with 83,000 miles on it. There is only about 2 mpg hit from 65-75. I also own a 2013 with the ecoboost with max trailer, 3.73 gears and tow mirrors. Ive found that it gets very good gas mileage in a very specific manner. The advantage I have is being a mechanic many years ago. I can tell the second the turbo is boosting and calling for additional fuel. The key to the 2013 ecoboost is using an incredibly light foot and small changes in throttle when on the highway. For 5 years my son attended a military school near Richmond Va. we live in Cleveland and twice a month we drove down to see him over the liberty weekend. Going down we always got 21-22 mpg but coming back up 19-20…. The average speed on the highways was 65-70. Her in the deal.. if I used cruise control I lost 1-1.5 mpg. The cruise was more aggressive attempting to maintain the assigned speed. If I didn’t pay special attention to my driving, I averaged 14 city and 19 highway. I believe Ford rates the truck at 15/20. I’ve found all turbo vehicles struggle with the average driver to achieve their best possible mileage. Diesels on the other had generally produce better mileage than the rating on the sticker. If I could talk GM into it, they would make a hybrid diesel with a battery large enough to give the vehicle 20 miles EV only. This would see a significant drop in fuel use in city driving.

[@firefighter4443]

Yes!!! Where are all the Diesel hybrids? Can you imagine the mileage on a Diesel Prius?

[@PK-vd3vo]

Regarding turbos, what it comes down to is that it essentially behaves like a variable displacement NA motor. Force more air means forcing more fuel to keep the AF ratios correct. It is just so easy to go from vacuum to boost that one ends up pushing a turbo motor to be effectively 30-80% larger than the default displacement. Then they wonder where their mileage went.

[@DJ-wk5up]

2023 Sierra SLT, 18 in wheels, with the 3.0, Toronto Ontario to Halifax Nova Scotia at 105km (65mph) 42 mpg average on trip

[@poppyneese1811]

I can go to Lewisburg West Virginia from Bluefield West Virginia, one way is all highway 70mph and the other way is all two lane where I’m guessing 57 mph is tops and mostly sub 50 mph, my 2.7 Ecoboost F150 4wd supercab 3.73 rearend on the highway shows around 22.8 mpg on the highway, but on the old winding 2 lane when I arrive I’m getting an indicated 26.5 ads only about 10 minutes to the trip. I was shocked by the difference, I’m old and pretty light footed and the Ecoboost is a lil like a diesel, all the torque is below 3,000 rpm and it’s rarely above 1,500 rpm on the old road. 33.08 mpg for that good looking GMC diesel rig is outstanding! Great Video.

[@HPDrifter2]

Aerodynamic drag increases to the square of speed, so two times as much speed creates four times as much drag. A small increase in speed creates a large increase in drag, and a commensurate increase demand for power, and therefore fuel.

[@OutdoorGirls7]

It would take almost 9 more gallons of diesel to drive the same “one tank” range (20 gallons) going 75 vs 65. Costs about $35 extra to save 70 minutes of time. Driving the speed limit saves 43% of fuel costs, but only saves 20% time.

[@GearsGadgets]

@@OutdoorGirls7 BUT what is more valuable time or money. Do the same 20% of time calculation for one tank of life 😏.

[@dastarddizaster]

I had a 2008 Ram 3500 Crew Cab Dually that weighed 7500lbs with a full tank. It had a larger turbo and EGR delete and EFI Live tune. I averaged 26mph on a 5600mi highway round trip. These speeds were between 55 and 90mph. I thought that was amazing for a 6.7.

[@rocks2rocks06]

I can say from personal experience, in my class A RV 37'. The difference between 65 mph to 75 and mpg verses 65 down to 55. I will loose +100 miles of range going 75 if I'm towing its more. And going 55 I only gain around 25 miles in range covering the same path.

[@WJV9]

Dropping the tailgate would help with wind drag particularly at 75 mph. An even better option would be to put a cover over the truck bed to reduce wind drag.

[@andrewjackson9706]

I have a 20024 1500 LT LZO diesel 4x4 with the 18 inch rims and I get right around 33 with mostly highway. Best I have gotten was 60 mph and got 38 mpg.

[@tman9517]

Similar results in a 23 Yukon with the same engine. I couldn’t believe it until I drove it over and back Snoqualmie pass over the last year.

[@johnruff4025]

I had one GMC truck. It was beautiful but also the worst truck I ever owned. Was in the shop at the dealer more than my home for the first six months and each time, the mechanics knew exactly the problem before looking. Bad welds, bad wiring, etc. They said the engineers and builders would not listen to them so they had to fix all the new vehicles when they came in. Owned 5 Ford trucks and no issues with any of them. Retired and have a Tacoma now.

[@3.0dmax]

My 2020 Z71 RST gets ~29 average at 70 (typical limit here), minimal wind, flat land. The aero shutters help a bit, but expect quite the loss if you're driving into a 20MPH headwind. Is what it is, a brick on wheels. But yeah, GM made a winner in my opinion. My advice is to stay on top of oil change interval. 5k or 20%. I change my fuel filter every 10k no matter what. Cheap and easy DIY.

[@travisyarbrough4033]

So .... The 65 syndrome is rude rideshare sometimes. I stay right every time when on a rideshare app. The app will flag me and I can get taken off for going over. Slow vehicles need to stay right and other people should use all the other lanes and not road rage those of us trying to stay on the platforms. YES those trucks get that at those speeds. I met a guy who gets 28 in a diesel dually. He had print outs and everything from Bank's from the tests. Thanks for the truthful test sir.

[@Veterans-e2c]

Nice truck. Who cares what people say. Great video. I have 2024 GMC sierra Denali with the duramax I see similar numbers.

[@rdsii64]

Speaking of the ford you used to drive. As much as I love fords, I wish the other companies would offer their own take on the powerboost hybrid option. I would love to see some competition in that space.

[@GearsGadgets]

I totally agree although I’m slightly gun shy now on that complexity after what I went through. I honestly started shopping around for old used 5.3 liter chevys after my Ford but I decided to give new one more chance before I just completely give up.

[@timgurr1876]

The question is whether you filled the tank to full. I’ve heard that you should wait 30 seconds after the first shutoff of the hose. Then continue to fill until it clicks off. Sometimes air gets trapped in the tank and it takes time for it to bubble out. Regarding lane selection, I think it would make more sense on over lanes to have the center lanes be the fast lane. Many people do not like to change lanes, especially at high speeds and nearly bumper to bumper traffic (i.e. rush hour), so they immediately migrate to the lane that gets them the easiest access to their exit point. Thanks for the video. I’ve often wondered MPG with the Duramax engine.

[@shanefesler997]

Best I’ve got with my 2024 Chevy Silverado with the Duramax has been 37.1 MPG.

[@wb5mgr]

So I’ll add this is a data point. I have a 2021 GMC 2500 HD with a Duramax and day in and day out city and highway driving mixed over the last 25,000 miles according to the dashboard I’m averaging right at 15.9 miles to the gallon. I just did a 400 mile road trip today and on that trip I averaged about 21 miles to the gallon on the highway and this 8000 pound truck. Not pulling a trailer or with any kind of heavy load just deadheading. That being said, I recently took a trip that included driving a section of the Natchez trace Highway which is 50 mile an hour speed limit and I did 55 mph, which is about all you can get away with without being in jeopardy of getting written up by a park ranger, for the 50 miles that I was on the trace I was averaging 29 miles to the gallon. That’s incredible in a truck this size. I have a friend that owns a vehicle just like yours and he took a trip on the trace and told me that he got in the mid-40s for mileage with the 3 L Duramax. There is a reason why back in the day Ronald Reagan changed the speed limit to 55 miles an hour. Because it was the most effective way to improve the economy and conserve petroleum usage. For a good portion of my life, it was the national speed limit. I remember being excited when it went back to 65 and then to 70 or 75 in some places. But that was just in the last 20 years or so. We used to drive on the interstate at 55 miles an hour. Just think about it. But there’s no better way to add to the fuel economy of your vehicle, then to reduce the speed at which you drive. I’ve tried the same experiment in my previous truck, which was an F150 with a 5 L. It work just as well. Gas or diesel driving slower get you better mileage. Of course, it has its practical, limitation.

[@kenpatton8761]

Wasn’t Regan…Nixon changed the speed limit to 55 mph in 1974. I now drive a 2020 GMC 3500 dually diesel toting a massive truck camper. I try to keep my speed to 65 mph mainly due to the weight of the camper and stopping distance needed. I have plenty of power to pass just about everyone on steep inclines/mountain passes if I need to. And my mileage is a lot better too. Cheers

[@jeffwatson8862]

2000 Dodge ram 2500 2wd cummins 5.9. If I keep it under 2000 rpm = 73 mph I get 22 to 23 mpg. Bump it up to 80 mph and back to 18 mpg. This on my trips to Cali from Phoenix in the 22 years I've owned the truck.

[@geraldkoth654]

Had a nice 1994 Cadillac Fleetwood with the corvette motor in it. Best mileage was at 115 mph 27 mpg. 125 fell off to 23 mpg, 105 was 21 and 85 was 19. Wife would drive too slow and run out of fuel on the 400 mile trip to her daughters house. My Dodge Ram Cummins is 17 years old and runs better than when it was new.

[@jimsgaragetoys]

On most of your shorter trips you won't save much time doing 75 vs 65. I've never felt that I'll get hit if I'm driving slower than others, they just move around me. I save my fun for when I'm away from traffic and the city as driving 75 vs 65 isn't much of a difference to me. I don't mind relaxing and chilling to some music and for an additional 10 mpg like you saw, that will add up quickly.

[@427Ron]

That was a great video and that’s a nice rig

[@chrism2042]

I test drove a tahoe with the 3.0, nice ride and better fuel mileage than my Tahoe with 5.3 gas. I was hesitant to trade with some of the known issues with the 3.0. I have a 2017 Ram 3500 dually, limited LB, 4x4, HO 6.7 with aisin trans, geared 3:73. I make trips where I am driving approx 100 miles on I40 with cruise set on 75 mph, then 70 miles on another highway with cruise set on 60 mph, no stop and go. It is almost the same every time I check mileage at the pump. At 75 mph I get 19.2 mpg and 60 mph I get 22.5 mpg

[@1AXMRDR]

I have an 02 F350 4wd 7.3 and the mileage takes a hit over 2k rpm. (about 70 mph). Driving 55mph on secondary roads it gets pretty good mileage. I live where secondary roads are curvy. I use cruise control most of the time. Best I have ever gotten is 18 mpg but usually get 14 driving as fast as I care to drive. I didn't buy this truck for mileage, I bought it to pull a mountain if I want to.

[@jimtuccillo4786]

The power required to overcome air resistance essentially goes as the cube of the velocity. Take the ratio of 75 cubed to 65 cubed and that will be a close approximation to the the ratio of the miles per gallon. In this case, it is only off by about 10%. Small difference is speed have a big impact on miles per gallon as the speed increases because of the cubed factor. Good video.

[@michaelmccolm2415]

Correct. To double the speed for a given vehicle requires 8 times more power (2 cubed , or 2x2x2). All that power comes from fuel.

[@dannyleach6232]

60-65 on the highway with 35’s 28-29 not adjusting for speedometer being off. Love mine. 97k miles

[@JS-ov9jb]

Your anxiety when going the legal speed limit was hilarious. It's a similar situation here, the speed limit is dangerously slow most days. Nice truck, stay safe!!

[@GearsGadgets]

Very anxious. Not something I enjoyed at all.

[@kenlane8484]

2016 sprinter 2500 4cy terbo diesel...long model..full 2motorcycles all gear plus luggage 2 people..26 mpg..at 65mph..at 75mph 18mpg your right..Savings on round trip to Florida $$$$

[@andyfoley6906]

Wow, 33mpg at 65! That is amazing with a pickup! Wonder what you’ll get around town local driving. Had to laugh Dan when you talked about the electric cars. Over here in Florida it’s usually the opposite. The Teslas are usually doing 90 in the left lane. We have a problem with Prius doing 70 (our highway speeds) in the fast lane while most of us are doing 80.😊

[@GearsGadgets]

Ahh yes I forgot to mention the Prius lol. I will post a video on long term more "realistic" day-to-day MPG.

[@wesharris07]

It’s crazy to see the results. Great video. I am not a loyalist either. But I will say I agree with you the seats in the GMC/Chevy are a lot harsher. Than the fords. I like the options in the ford but I love the diesel in the GM trucks. Decisions…. 🤔🤣

[@GearsGadgets]

I have to say at first impression I didn’t like the GMC seats but after running two 85 mile loops with this new truck, not one time did I feel uncomfortable. I don’t have a great back so I’m actually starting to think maybe the firmer seats are offering better support for me. Seats are obviously super subjective though and will be different for every driver.

[@wesharris07]

@@GearsGadgets nice. I’ve only done the test drive. So that’s not long enough to make a full on review on the seats. That’s good to know you like them more now. The 33mpg is phenomenal.

[@garysarratt1]

Sometimes I think my LTZ seats aren’t good enough, but my wife’s Buick Enclave seats change my mind quick.

[@williamcrist1887]

I do believe your findings I have an F-350 Dully and the difference between 65 and 70 is 3-4MPG now granted I am running 4:10 gears but it’s not a speed demon

[@jefffunkhouser2773]

Speed kill MPG. I took a trip with my truck and trailer to get a other piece of equipment , I did 70 mph going down to get it and I used half tank going down and I took a other way coming back. ( It was longer to) and I was do 55-60 back on 1/4 of a tank

[@willdrivesu7914]

This is true for all vehicles, fast aggressive driving lowers your mpg and causes more wear and tear on the engine and other components. Not slowing down after seeing this much of an impact on your mileage is foolish at best and a huge waste of money. But that's your choice. It should also be noted that force multipliers increase significantly in an accident at higher speeds, making it more likely to kill yourself, your passengers, or someone else on the highway.

[@doughaven-rf8id]

With a small car adding two kayaks on the roof and driving in a strong crosswind is like leaving the park brake on. lol

[@darrinstone49]

My 01 weighs 8k with a 6bt cummins I get 16 towing & 19 average. At 85mpg it drops to 16-17mpg empty. Aerodynamics makes,a big difference too when we drop the air in the bags, as low as possible it goes up too.

[@truetexan7755]

I think a lot of people drive in the left lanes ,regardless of speed, is because the far right lane is always fucked up ( full of potholes) because of heavy comercial trocks and such.

[@garrybrischke53]

Just imagine the fuel savings if everyone drove to the speed limit .

[@doughaven-rf8id]

The aggressiveness accelerating from a stop and on ramps is a huge factor as well.

[@khj697]

These differences always happen with trucks/ SUVs built on truck like frames. I’m in Texas where it’s common to have a speed limit of 75, down near Austin there’s a stretch where the speed limit is 85, and over in New Mexico most often the speed limit is 65. I had a Camaro with the 6.2 and 10 speed, and as long as you set the cruise control, it really didn’t care how fast you were going, it would deliver over 30 mpg.

[@GearsGadgets]

Yeah I’m sure especially with a Camaro having a way better coefficient of drag combined with the 10 speed.

[@100pyatt]

My 2018 4x4 3.0 Powerstroke super crew SB is similar 33hwy @66mph but at 75 mph it's 27.5 mpg..... this is with the 2wd lower air dam modification as well

[@andrewwood7217]

Mileage also was improved by cooler air (night temperatures) to the diesel engine (more efficient) and with the cooler conditions your auto climate control used the AC compressor much less often too (better fuel economy)

[@Grumpyoldman666]

The difference in my Wrangler is insane over 60-65

[@TheBurzhuy]

When you didn't learn science at school the whole world is mind blowing😂 😂😂

[@TheBurzhuy]

Even energy of a moving object depends of object velocity squared. That means for the same object with mass going 65 MPH (29,0576 meters/s) and 75MPH (33,528 meters/s) the difference in energy will be 33% and this energy gets from the source - fuel. Adding some losses due to drag coefficient and other losses the difference can be even bigger.

[@roundstone2020]

Well said.

[@WJV9]

@@TheBurzhuy - It's particularly bad for a big truck like this with open truck bed and tailgate which causes lots of wind drag at higher speeds.

[@doughaven-rf8id]

@@WJV9 Actually not. It seems like that would be the case. With the tailgate open the aerodynamics change creating turbulence thus hurting MPG. This has been independently tested and proven by Myth Busters and NASCAR race truck teams. Bed covers may give a slight improvement in economy but if you buy one just for MPG it's probably not worth it.

[@RustySax1949]

@@TheBurzhuy - I seem to remember from somewhere that the wind resistance alone increases by the cube of the speed differential. Maybe that's related to the coefficient of drag calculations? Maybe this comes from my high school physics class (which nowadays was back in the paleolithic era!)

[@davidglazener7210]

I have a 2003 SS Silverado. 55mph =20mpg. 65 mph = 17mpg. 75 mph = 15mpg. All that with 4.10 awg 6.0 engine. Add 10 mph wind and it all drops 2mpg across the board. This is driving from Colorado Springs to Kansas City.

[@jasonbroom7147]

If you really want to have fun, keep doing these tests at lower and lower speeds. You'll find that the best mileage comes when you are in the highest gear, at the lowest possible RPM, without upshifting. I drive the speed limit or a few miles over, but also kinda got into the "hyper-miling" thing a while back. I found I could get 7-12 mpg more, even from a little econobox sedan, by using those driving techniques. I don't bother anymore, but it's a good thing to know if you're ever really low on fuel and trying to make it to a gas station.

[@crabbypapa3862]

Our 1982 Grand Marquis consistently showed Under actual MPG. A rental 2022 Corolla showed More than actual. Different vehicles can show variances. I record my fuel use and mpg, disregarding the computer. Try not to drive on empty on long trips especially. My 2000 Grand Marquis actually gets optimum at 75 to 80. Depending on wind, and who is driving. The more braking and accelerating the worse your highway mpg can be.

[@raywaage7550]

Stay slow enough and accelerate gently enough to stay out of boost, and you’ll see huge mpg gains.

[@bobmartens1089]

I tow a travel trailer with a 14 F150 5.0 across country and get about 13mpg cnd at 63 mph which is the sweet spot for my set up. If i go 65 to 70 my mpg drops to 8 or 9.

[@CarnivoreKipp]

Can you turn off buckle to drive? And if so does the think continuously ding or does it stop.