Fuel Milage issue?

[MaDDscientist]

New to the group, so if I misstep any rules here, my apologies…

Bought a 2024 Gladiator Sport S with Max Tow in November. I love it, but I see threads where people are saying they are getting significantly higher MPGs than I am seeing. I’m wondering if there is an issue somewhere…

With the stock wheels and tires, I averaged right at 16mpg, mostly highway driving. Now, I’ve installed 285/70/17s, and my milage has dropped to 14… (Falken Rubitrek)

I expected a drop with the new wheels and tires, but the overall mileage seems low to me. Any ideas?

For context, in Western West Virginia, so some hills, but I wouldn’t call them mountains. Vast majority of my daily drive is Interstate…

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[Maximus Gladius]

I would think roll resistance has changed with the different tire. Also, if you haven’t yet, have the new size calibration done to the transmission and odometer. You may then see the numbers you’re used too.

 

[Billkowski]

New to the group, so if I misstep any rules here, my apologies…

Bought a 2024 Gladiator Sport S with Max Tow in November. I love it, but I see threads where people are saying they are getting significantly higher MPGs than I am seeing. I’m wondering if there is an issue somewhere…

With the stock wheels and tires, I averaged right at 16mpg, mostly highway driving. Now, I’ve installed 285/70/17s, and my milage has dropped to 14… (Falken Rubitrek)

I expected a drop with the new wheels and tires, but the overall mileage seems low to me. Any ideas?

For context, in Western West Virginia, so some hills, but I wouldn’t call them mountains. Vast majority of my daily drive is Interstate…

Doing better than me, lucky to average 15....other people must drive very gingerly.

 

[MaDDscientist]

I would think roll resistance has changed with the different tire. Also, if you haven’t yet, have the new size calibration done to the transmission and odometer. You may then see the numbers you’re used too.

I have updated the tire size…. MPGs match with manual calcs…. Maybe I just have a lead foot…

 

[Undecided]

May be slightly low. Also max tow and same tire size, checked weight is close enough for tire model and I get 16/17 during winter.

Are you remote start/warming up often/for a while ? When I do that it easily knocks out another MPG avg from dash calc.

 

[mdyucca]

When I see the posts with gas Gladiators getting 22-26 mpg I questioned why my mpg is so low also. Like you I have changed the size of my tires from original. I put on a set of Rubicon takeoffs. When mine was stock I would get 20.5 straight freeway driving with the new tires I can get 20 mpg straight freeway driving. With all my modifications (larger wheels/tires, front steel bumper/winch, bed cover, Molle panels, air compressor, lighting/switch systems you get it) I average 13.5-14 between fill ups. I do not consider the Jeep Gladiator to have great fuel economy. However, considering what it is, 4X4 mid size pickup loaded with all the equipment I carry maybe 13.5 to 14 mpg is not bad for around town driving. Like you I had hoped for better fuel efficiency.

 

[MaDDscientist]

May be slightly low. Also max tow and same tire size, checked weight is close enough for tire model and I get 16/17 during winter.

Are you remote start/warming up often/for a while ? When I do that it easily knocks out another MPG avg from dash calc.

Yes, I am using remote start. I hadn’t considered how much impact that would have…

 

[rr11]

The remote start will have some effect on MPG, unless you idle a lot should not be huge. Several things effect the gas millage. My 2020 Sport S averages 20 on the highway, 17 to 18 in town. I had Rubicon takeoffs installed when I took delivery. Terrain affects your MPG . In Fl my drive is flat compared your daily drive.

 

[Labswine]

Yeah, remote start idling will bring down your MPG because it's basically 0 MPG whilst sitting there warming up. I only use mine on extremely cold days (like today, it was a balmy 8 degrees at 7AM today).

I have the Overland (ordered 5/19, delivered 7/19) and it's stone stock, even still has the factory tires and, I typically get a little over 21 MPG bopping around in the summer and 20 MPG in the winter. I also get between 12 and 13 MPGs towing my 27', 5,100 lb (with all we want or need) travel trailer.

I took a trip a week after I got it and averaged 23.5 MPGs on that trip (Philly area to Boston and back).

The best I have seen on straight highway driving, interstate/turnpikes, with the cruise set at 70 MPH was 26.7 MPG, calculated fill to fill, and the average for that trip was around 25.5 MPGs. That trip, when I got into northern Michigan and the speed limit was 75 MPH (do at LEAST that or you get run over...) and my mileage for that tank dropped to around 23 MPG so, yeah speed kills...your fuel economy.

I will probably lose 1/2 a MPG or so when I replace the factory 255s with 265s. Getting rid of those Dueler HTs (currently 37 K on them) and going to go with Hankook Dynapro ATms. Had them on another Jeep and they were awesome in the snow and wicked quiet on the highway.

 

[SoK66]

Hmm, that doesn't sound right. First, you have to have the system recalibrated for the new tire size to get the speedometer accuracy and the RPMs/transmission shift points back in synch. At that point you should see improvement in driveability and mileage.

Bear in mind, with the Max Tow you go the wider axles and 4:10 gear ratio. Performance will be better with the 4:10s than the 3:73s found in the other axles, however mileage will suffer.

For reference, the morning after I brought it home I swapped out the wretched 255 BFG KM2s that came on on my then new '23 Willys 3.6 to Rubicon/Mojave size 285 BFG KO2s. The difference is essentially going from 32s to 33s (not exactly, but read on). The change threw the speedometer off by about +2 MPH at 60. I got the contraptions (iCar Pro dongle & wiring pigtail) necessary to use Jscan to recalibrate the PCM. That got ther speedo dead on per GPS. Mileage since then has been 18 - 22 mpg. I live at 7400 ft in mountain terrain.

 

[red/green hawk]

I switched to using nothing but ethanol free gas. If I absolutely have to, I'll put in 92 octane with ethanol if it's the only thing available. I've noticed increases of 1-2 mpg in winter and 2-3 mpg in summer. Running 285/75 Yokohama G015s. I'm getting a little over 18 mpg in winter and 21 mpg in summer. 70 mile per day round trip commute to work on an uneven split highway with speed limit of 65 mph. Let it also be noted I have a 6.5 mile 7% grade to contend with. Moral of the story the ethanol free gas is more expensive but I think worth it over a long period of time.

 

[MaDDscientist]

Hmm, that doesn't sound right. First, you have to have the system recalibrated for the new tire size to get the speedometer accuracy and the RPMs/transmission shift points back in synch. At that point you should see improvement in driveability and mileage.

Bear in mind, with the Max Tow you go the wider axles and 4:10 gear ratio. Performance will be better with the 4:10s than the 3:73s found in the other axles, however mileage will suffer.

For reference, the morning after I brought it home I swapped out the wretched 255 BFG KM2s that came on on my then new '23 Willys 3.6 to Rubicon/Mojave size 285 BFG KO2s. The difference is essentially going from 32s to 33s (not exactly, but read on). The change threw the speedometer off by about +2 MPH at 60. I got the contraptions (iCar Pro dongle & wiring pigtail) necessary to use Jscan to recalibrate the PCM. That got ther speedo dead on per GPS. Mileage since then has been 18 - 22 mpg. I live at 7400 ft in mountain terrain.

I used ODB JScan to update the tire size. And I have verified the Speedo with GPS. Hasn’t helped. Honestly, I just want to make sure something isn’t wrong…

 

[OldSarge]

New to the group, so if I misstep any rules here, my apologies…

Bought a 2024 Gladiator Sport S with Max Tow in November. I love it, but I see threads where people are saying they are getting significantly higher MPGs than I am seeing. I’m wondering if there is an issue somewhere…

With the stock wheels and tires, I averaged right at 16mpg, mostly highway driving. Now, I’ve installed 285/70/17s, and my milage has dropped to 14… (Falken Rubitrek)

I expected a drop with the new wheels and tires, but the overall mileage seems low to me. Any ideas?

For context, in Western West Virginia, so some hills, but I wouldn’t call them mountains. Vast majority of my daily drive is Interstate…

Assume you have the 3.6? Sounds right to me. These engines are not terribly efficient - might as well be driving a V8! Would be a lot more fun.

 

[MaDDscientist]

Assume you have the 3.6? Sounds right to me. These engines are not terribly efficient - might as well be driving a V8! Would be a lot more fun.

Yes, 3.6…

 

[Figmo]

I used ODB JScan to update the tire size. And I have verified the Speedo with GPS. Hasn’t helped. Honestly, I just want to make sure something isn’t wrong…

My 22 Rubi gets 14-15 MPG on highway. I don't think anything is wrong. The Gladiator body style can hardly be called a "slipstream design". It's a big-ass box on wheels and pushes through the air like a snow plow.

Note: highway speed will effect economy. The faster you drive, the bigger that pressure wave in front of you. I live in a rural area and everything is "half hour" away from everything else. So I tend to cruise around 80-85 MPH normally.

I figure I could probably squeeze another MPG out of her if I slowed down a bit, but....hey....life's too short to slow down, no?

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