Sponsored

37's and MPG

tjeeper

Well-Known Member
First Name
Patrick
Joined
May 7, 2017
Threads
13
Messages
169
Reaction score
229
Location
Utah
Vehicle(s)
'99 TJ, '24 392
12-13. This is at 80-85 mph, and it usually is windy in Utah.

City about 14-15.
Sponsored

 

DodgeZ

Member
Joined
Mar 21, 2020
Threads
5
Messages
24
Reaction score
6
Location
Texas
Vehicle(s)
Jeep JL
Anyone change gears and get better performance and mileage?
 

Gorilla57

Well-Known Member
Joined
Jan 3, 2019
Threads
11
Messages
974
Reaction score
1,394
Location
Chandler AZ
Vehicle(s)
2019 JLUR Mojito
37’s on TR beadlocks and 4.88’s......15 around town, 15 on the highway. Not great, but not bad. 75mph just kills mpg. If I stay 65mph, I’ll get 17-18mpg.
 

DodgeZ

Member
Joined
Mar 21, 2020
Threads
5
Messages
24
Reaction score
6
Location
Texas
Vehicle(s)
Jeep JL
37’s on TR beadlocks and 4.88’s......15 around town, 15 on the highway. Not great, but not bad. 75mph just kills mpg. If I stay 65mph, I’ll get 17-18mpg.
were the gears worth it?
 

Gorilla57

Well-Known Member
Joined
Jan 3, 2019
Threads
11
Messages
974
Reaction score
1,394
Location
Chandler AZ
Vehicle(s)
2019 JLUR Mojito
were the gears worth it?
I would say yes. Jeep doesn’t struggle at all and it uses all 8 gears. It accelerates just as fast on the on-ramps and passes cars easily on 2 lane roads. This thing is just a brick at highway speeds and the lift, tires, wheels, armor, etc all combine to kill the MPG.
 

Sponsored

Dkretden

Well-Known Member
First Name
David
Joined
Jan 29, 2019
Threads
57
Messages
2,533
Reaction score
3,527
Location
Denver, CO
Vehicle(s)
2020 JLUR 3.6L
High 17's / low 18's around town driving. High 18's / low 19's highway 4.10 gears 3.6l
This is quite great. I am lucky to get 16mpg around town (urban) with my unmodified rubicon. Good stuff.
 

gbr

Well-Known Member
First Name
Gerald
Joined
Nov 11, 2019
Threads
14
Messages
312
Reaction score
910
Location
Canada
Vehicle(s)
2020 JLUR
37" Milestar Patagonia and 3.5" Metalcloak Gamechanger.

City: 17.7 if I drive really careful.
Hwy: 19 if I stay around 60-65 MPH

Stock 4.10s.
 

Gorilla57

Well-Known Member
Joined
Jan 3, 2019
Threads
11
Messages
974
Reaction score
1,394
Location
Chandler AZ
Vehicle(s)
2019 JLUR Mojito
And just an FYI for those wondering about MPG. Don't necessarily believe the high numbers people claim to get. Are they hand calculating and did they add a Tazer or something similar to adjust tire size, gear ratio to get the odometer/speedo right? My numbers are low and it's due to all my extra weight and lift height. But, my tire size and gear ratio is adjusted via a Tazer, speedo is GPS verified and I hand calculate my MPG. I hit 8th gear by 50mph and just purrs along nicely at that speed. I knew I wouldn't get stock MPG numbers ever again, but I'm ok with that.
 

DodgeZ

Member
Joined
Mar 21, 2020
Threads
5
Messages
24
Reaction score
6
Location
Texas
Vehicle(s)
Jeep JL
And just an FYI for those wondering about MPG. Don't necessarily believe the high numbers people claim to get. Are they hand calculating and did they add a Tazer or something similar to adjust tire size, gear ratio to get the odometer/speedo right? My numbers are low and it's due to all my extra weight and lift height. But, my tire size and gear ratio is adjusted via a Tazer, speedo is GPS verified and I hand calculate my MPG. I hit 8th gear by 50mph and just purrs along nicely at that speed. I knew I wouldn't get stock MPG numbers ever again, but I'm ok with that.
My question is... do you need gears? Do you get better mileage with 37s if you regear
 

Gorilla57

Well-Known Member
Joined
Jan 3, 2019
Threads
11
Messages
974
Reaction score
1,394
Location
Chandler AZ
Vehicle(s)
2019 JLUR Mojito
My question is... do you need gears? Do you get better mileage with 37s if you regear
You need gears in order for the engine and trans to “try” and work like normal. You’ll never get the stock 4.10’s to push the 37’s as nice as 4.88’s will. Simple physics. I’d do it again.
 

Sponsored

Petey003

Well-Known Member
First Name
Adrian
Joined
Mar 29, 2018
Threads
21
Messages
121
Reaction score
57
Location
Southern Vermont
Vehicle(s)
2021 RAM TRX, 2018 JLUR, 1996 H1 Wagon
Occupation
Director of Commercial Operations (TWF)
Vehicle Showcase
2
What kind of mileage are you guys getting with 37's and the 3.6L?
18.5mpg 72-77mph
20.5mpg 62mph

37" General Grabber X3's (81lbs)
4.88 Gears in JLUR Auto
 

Varilux

Well-Known Member
First Name
Pete
Joined
Dec 29, 2018
Threads
16
Messages
320
Reaction score
682
Location
Hickory Creek, TX
Vehicle(s)
2018 Jeep Wrangler Rubicon
Vehicle Showcase
1
I keep a notebook in which I track (among other things) every tank of gas... yes, I know I have OCD.

With the stock 33" tires (before I deleted the spare), I was getting 17.7mpg (70% highway, 30% city).
With the stock 33" tires (after I deleted the spare), I was getting 18.8mpg (same split of driving).
With 37x12.5" Nitto RidgeGrapplers (used Mini-Tazer to reset tire size and still no spare), I get 16.7mpg.
 

No IFS

Banned
Banned
Banned
Joined
Nov 13, 2019
Threads
10
Messages
1,167
Reaction score
2,306
Location
So Cal
Vehicle(s)
JL Rubicon
When I did my 37’s noticed that my miles per gallon dropped a little but my smiles per gallon went up a lot, so it’s a push. Lol
 

efitzger

Well-Known Member
First Name
Erik
Joined
Dec 23, 2018
Threads
11
Messages
157
Reaction score
112
Location
Evergreen, CO
Vehicle(s)
2018 JLU Rubicon
High 15's mixed driving at elevation with stock gears and heavy 37x13.5 Cooper STT's. I can eke out 17-18 on road trips if I keep it around 65. Anything above 75 and it starts dropping really quickly.
 

Gorilla57

Well-Known Member
Joined
Jan 3, 2019
Threads
11
Messages
974
Reaction score
1,394
Location
Chandler AZ
Vehicle(s)
2019 JLUR Mojito
A little update/addition to this thread. Helped nurse home a broke down truck from Flagstaff to Tucson yesterday. We peeled off when we hit south PHX, they were doing fine by that point. Averaged 62mph and got 19mpg. I was plenty happy. Got 15.0mpg going up to Flag going 70-75mph.
Sponsored

 
 



Top