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Bigger Tires, Better MPG on 3.0?

Industrialwrench

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Those numbers seem low.

Massive weight? Low tire pressure? Always driving in the rain / fog? High speed? Throttle fully engaged? Sails engaged? Computer not calibrated?
Yes to all of the above? Taser mini on order but it’s a stick so I don’t see how it will change much, but it’s not looking that good. I’m in the mountains and going up hill 2500-3000 seem to be the spot. Milage is junk. Wheel weight is significantly higher. I don’t care much really, I didn’t buy it for the milage and have other vehicles to use if I want.
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Ratbert

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Yes to all of the above? Taser mini on order but it’s a stick so I don’t see how it will change much, but it’s not looking that good. I’m in the mountains and going up hill 2500-3000 seem to be the spot. Milage is junk. Wheel weight is significantly higher. I don’t care much really, I didn’t buy it for the milage and have other vehicles to use if I want.
If you're using the mileage displayed on the dash then hopefully you realize that it's wrong and your real mileage and speed are both higher than what the dash says. That might be a useful detail if there are any concerns about getting a speeding ticket.

This is assuming, of course, that you haven't also re-geared.
 

grimmjeeper

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Yes to all of the above? Taser mini on order but it’s a stick so I don’t see how it will change much, but it’s not looking that good. I’m in the mountains and going up hill 2500-3000 seem to be the spot. Milage is junk. Wheel weight is significantly higher. I don’t care much really, I didn’t buy it for the milage and have other vehicles to use if I want.
If you have a stick shift you have the 3.6. That gas engine gets teens for mileage. The best you'll do is touch the 20s.

This thread is about the 3.0 diesel which only comes with the automatic transmission. It's an entirely different animal.
 

Industrialwrench

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Oh I know it’s a gas engine with a manual. And I know the milage and the Speedo are off from the increase of tire size. I’m just giving some data. Yes my milage is terrible. Yes it would be better with the your fuel source. No you will not get better milage with bigger wider tires no matter what engine or transmission you have.
 

JL Diesel

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23 JLURD, 3.5" Metalcloak Lift, 37" MT Baja Boss A/T, 3.73 gears, 35 psi cold. Tazer corrected tire size verified speedometer with gps. Getting 16.5 MPG over 420 freeway miles from Los Angeles to Cedar City. Some wind and driving at the speed limit, 70-80. About 5000' gain in altitude. Got 28 MPG at 65 MPG when fully stock. Hoping for better on the downhill return trip.
I know that drive well but from San Diego. Definitely got better mpg on the way home. I’m only have 2.5” Metalcloak lift on 35” Nitto Ridge Grapplers but I got 26mpg overall on our last trip. The wind direction in the stretch between Vegas and Mesquite makes a world of difference on the mpg.
 

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Floriduramax3.0

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2020 over 4" lift 40" Pat M/T-02"s 4.88 gears homemade tune etc..18.5 cruise set at 70 everything corrected hand calculated. Will easily get in the low 20's 60-65 but cannot drive that slow! Absolute blast to drive when my wife gives me visitation rights or she hears a rattle!!
 

nsfw_andy

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23 JLURD, 3.5" Metalcloak Lift, 37" MT Baja Boss A/T, 3.73 gears, 35 psi cold. Tazer corrected tire size verified speedometer with gps. Getting 16.5 MPG over 420 freeway miles from Los Angeles to Cedar City. Some wind and driving at the speed limit, 70-80. About 5000' gain in altitude. Got 28 MPG at 65 MPG when fully stock. Hoping for better on the downhill return trip.
Have you chalk tested your tires? 35psi cold is quite a lot.
I run the same exact brand and size tires at 26psi cold and I still dont get a full contact patch, maybe about 1/2 of the outer lugs don't touch the pavement.
I tested going lower at about 24psi cold but don't like the way it drives and handles.
 

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AZDIESELRUBI

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I just installed Mickey Thompson Baja Boss MTs and Black Rhino Kelso Wheels. I only have about 1600 miles on it with stock wheels and was getting 23 MPG in town roughly. With 37in tires and the new wheels it looks like maybe it dropped 1 MPG?

The stock tires are 60lbs per tire and The Mickey Thompson Baja MTs are only 80lbs. The get up and go seems the same as stock, I did notice that prior to adjusting the tires size with the Tazer JL Mini the shift points seem to be off a little however. The speedo was 5MPH of as well.

Right now I cant see any need to regrear with the EcoDiesel.

Jeep Wrangler JL Bigger Tires, Better MPG on 3.0? 20230329_154615
 

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Jeffy56

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The stock tires are 60lbs per tire and The Mickey Thompson Baja MTs are only 80lbs.
I suggest re-evaluating that. Bigger tires usually means less PSI. Better ride too.

FYI. recently bought 2018 JLUS, 3.6, auto, 49k miles. I just went to 4.10 gears. Home 5000ft - visit 1200ft. 170-190 miles round trip depending on beer stops. 32.6 tire OD per (Falken)MFG, 32 psi. 65 mph average. Tire OD & gear ratio corrected with Taser. 21.8 avg. mpg.

Jeep Wrangler JL Bigger Tires, Better MPG on 3.0? 20230213_075219


Jeep Wrangler JL Bigger Tires, Better MPG on 3.0? 20230410_115805
 
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Tpsillos

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Jeep Wrangler JL Bigger Tires, Better MPG on 3.0? 42313BE9-9377-4DCC-82F2-701705848796
First 1500 miles on 40s, only down about 5mpg from the factory. Only other variables are some engine/tuning mods that did get me another 2 mpg from factory. Bigger tires equal worse milage no way around it.
Edit: should add that includes last weekends wheeling trip(30 miles in 4 lo and another 50 miles slow on trails)
 

Floriduramax3.0

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Jeep Wrangler JL Bigger Tires, Better MPG on 3.0? 42313BE9-9377-4DCC-82F2-701705848796
First 1500 miles on 40s, only down about 5mpg from the factory. Only other variables are some engine/tuning mods that did get me another 2 mpg from factory. Bigger tires equal worse milage no way around it.
Edit: should add that includes last weekends wheeling trip(30 miles in 4 lo and another 50 miles slow on trails)
Nothing wrong with that! I can't wait to see the Bronco posted mpg with 40's...lolol
 

zouch

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"some engine/tuning mods that did get me another 2 mpg"?!

if you've done something that got you any more MPG, please share!
also, what did you use for speedo/shift point corrections to compensate for the tire size change?

as an aside; 68K miles already on a '21? holy fook!


Jeep Wrangler JL Bigger Tires, Better MPG on 3.0? 42313BE9-9377-4DCC-82F2-701705848796
First 1500 miles on 40s, only down about 5mpg from the factory. Only other variables are some engine/tuning mods that did get me another 2 mpg from factory. Bigger tires equal worse milage no way around it.
Edit: should add that includes last weekends wheeling trip(30 miles in 4 lo and another 50 miles slow on trails)
 

Tpsillos

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LOL, i have driven the tar out of this thing. i dont take it easy as ive owned diesels most of my life. so i could probaby get better milage but idc. I modified it for the power alone. I work out of town and drive home on the weekend about once a month.

Reach out to Ecodieselownersofcanada. Their stage 2 system is nice, especially with the trans tune. just AFE intake and intercooler pipes besides that which was installed that same weekend so not sure how much they really helped but they look and sounds nice.
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