2019 JLUR 3.6 8speed, 4.88 gearing with 37/12.50/17 Getting 11.5 MPG

[lepcat]

What am I missing. I see so many of you posting with the same setups and averaging 14 to 16 MPG.

I have changed the tire size and gearing using the Tazer. Speedo is correct and I am averaging 11.5 mpg in town. And on a long road trip I might get up to 13 mpg.
Is there any additional changes that I am unaware of?

Thank you,

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[mnjeeper]

Have you done the math to see if it's correct on the computer?

 

[multicam]

Is that hand calculated based on actual gallons pumped and miles driven or is that number from the computer?

Either way, it does seem a little low but everyone’s situation is going to be different and you may just have a heavier foot than others. Hell, my Jeep’s computer is reporting about 11 mpg average right now and it’s bone stock.

 

[Some Random Guy]

You’re missing a pedal.
Sorry, couldn’t help it.
Serious now. Did you do your own gears or have a shop do it? Also, can you describe the shifting behavior? What RPM does it normally downshift?

 

[lepcat]

Have you done the math to see if it's correct on the computer?

As in tire size? Or what math do you speak of?

Ah, yes I have done the math for mileage. Not just going off of the EVIC.

 

[lepcat]

Is that hand calculated based on actual gallons pumped and miles driven or is that number from the computer?

Either way, it does seem a little low but everyone’s situation is going to be different and you may just have a heavier foot than others. Hell, my Jeep’s computer is reporting about 11 mpg average right now and it’s bone stock.

Ah, yes I have done the math for mileage. Not just going off of the EVIC.

 

[lepcat]

You’re missing a pedal.
Sorry, couldn’t help it.
Serious now. Did you do your own gears or have a shop do it? Also, can you describe the shifting behavior? What RPM does it normally downshift?

Gears were professionally installed (Before I purchased the Jeep)
Shifting behavior seems good as well. I have even used the I Drive throttle controller to try and gets some mph's back using economy mode.

 

[lepcat]

Have you done the math to see if it's correct on the computer?

Yes hand calculated MPG's

 

[conFUcius]

What tire size did you enter on the Tazer? Having used a Flashcal before, I made the mistake of entering my measured rolling diameter in the Tazer vs. the paper tire size (the Tazer has a percentage calculation).

 

[lepcat]

What tire size did you enter on the Tazer? Having used a Flashcal before, I made the mistake of entering my measured rolling diameter in the Tazer vs. the paper tire size (the Tazer has a percentage calculation).

I have it set at 36.88 I am running Mickey Thompson MTZ's

 

[conFUcius]

I have it set at 36.88 I am running Mickey Thompson MTZ's

Change it to 37 or whatever denomination is right above 37 and see how it does. I noticed a shifting issue vs. a mileage thing but since I changed it, no problem. Have a post on another thread about the shifting issue.

 

[lepcat]

Change it to 37 or whatever denomination is right above 37 and see how it does. I noticed a shifting issue vs. a mileage thing but since I changed it, no problem. Have a post on another thread about the shifting issue.

I'll give it a go. Is your speedo reading correctly?

 

[mnjeeper]

That hand calculated mileage deepens the mystery. I have 37s and 4.10s still and I do a few MPG better than you. (14 on short city type drives and 17 hwy)

 

[DavidArmen]

What is the weight of your tire + wheel combo? Stock rubicon wheels are only about 20lbs and the stock 33” ko2s are only 51lbs. That’s a total of only 71lbs. Beadlock wheels and heavy 37s can be twice as heavy (sometimes even more). Regearing can’t do anything about the doubling of the unsprung weight.

 

[lepcat]

What is the weight of your tire + wheel combo? Stock rubicon wheels are only about 20lbs and the stock 33” ko2s are only 51lbs. That’s a total of only 71lbs. Beadlock wheels and heavy 37s can be twice as heavy (sometimes even more). Regearing can’t do anything about the doubling of the unsprung weight.

I am using stock Rubi rims and my tires weigh 74.14 lbs.

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