MPG with 2.5 lift
JK Enthusiast
Joined: Jul 2009
Posts: 351
Likes: 5
From: Newcastle-upon-Tyne,UK
A Head wind on the freeway can get you stopping to check the callipers aren't binding
A good tail winds like you've just changed all the fluids
2.5" lift and 315/70/17's (4.10's) probably loosing 3-4 MPG
A good tail winds like you've just changed all the fluids
2.5" lift and 315/70/17's (4.10's) probably loosing 3-4 MPG
Last edited by RLT; Feb 10, 2015 at 10:16 AM. Reason: addition
JK Enthusiast
Joined: Oct 2012
Posts: 441
Likes: 0
From: Sanger, TX
Anybody know the drag coefficient with the top off? 
Sorry couldn't resist. If it's any consolation, for a 2-door with hardtop on, that at one time had 34's (33.7's to be exact) BFG KM2's (weight approximately 63 lbs if I remember right) on stock 18" rims with Teraflex 1.25 adapters, with the Pentastar and 3.73 gears, 2.5" lift, winch, PSC brawler lite front bumper, hi-lift jack, ace sliders, genright AL rear bumper + carrier, sPOD, ARB compressor, assorted tools in the rear cubby, running regular unleaded from either Shell or Chevron, no rear seat, and my 220 lb frame after lunch, moderate highway speeds of 65-70mph.....I think at that time I was getting about 18 mpg. 20 mpg if I was really easy on the pedal. 
Sorry couldn't resist. If it's any consolation, for a 2-door with hardtop on, that at one time had 34's (33.7's to be exact) BFG KM2's (weight approximately 63 lbs if I remember right) on stock 18" rims with Teraflex 1.25 adapters, with the Pentastar and 3.73 gears, 2.5" lift, winch, PSC brawler lite front bumper, hi-lift jack, ace sliders, genright AL rear bumper + carrier, sPOD, ARB compressor, assorted tools in the rear cubby, running regular unleaded from either Shell or Chevron, no rear seat, and my 220 lb frame after lunch, moderate highway speeds of 65-70mph.....I think at that time I was getting about 18 mpg. 20 mpg if I was really easy on the pedal. Sent using smoke signals
JK Freak
Joined: Jul 2013
Posts: 543
Likes: 2
From: Jersey Shore
Its funny all the regear threads and people who say 3.73 and 3.21 are fine with 35s.
Well as soon take the top down on the highway and do over 70 its horrible and 33 suck with the top down and some headwind.
Well as soon take the top down on the highway and do over 70 its horrible and 33 suck with the top down and some headwind.
Former Member
Joined: Apr 2012
Posts: 2,573
Likes: 2
From: USA
With all the other stuff mounted on, dropped down to about 15-17. With beadlocks and 35's, now I'm getting about 11-15. All depends how I drive. This is with the hardtop on. With the top and doors off, I'm enjoying the drive too much to even pay attention.
Once I re-gear it should get a little better.
Last edited by DJ1; Feb 10, 2015 at 08:00 PM.
JK Super Freak
Joined: Sep 2012
Posts: 1,564
Likes: 7
From: United States
When I'm wheeling, the ratio inverts itself, and fuel economy is measured in gallons per mile, and, "do I have enough fuel to get from here to there, and back?" All I know is the computer just keeps dropping its MPG estimate and DTE the whole time.
33's/3.73's/3.6/6-speed/2.5" lift/bumpers/winch/air dam removed, I took a 10% hit on road (about 2mpg, to my highway MPG) with all that stuff on my 2012 Sport. I can still average 19.5-20.0mpg if I keep it below 70mph and if winds are mostly neutral.
33's/3.73's/3.6/6-speed/2.5" lift/bumpers/winch/air dam removed, I took a 10% hit on road (about 2mpg, to my highway MPG) with all that stuff on my 2012 Sport. I can still average 19.5-20.0mpg if I keep it below 70mph and if winds are mostly neutral.
JK Enthusiast
Joined: Apr 2011
Posts: 305
Likes: 1
From: Edmond, OK
Nothing pisses me off about my Jeep more than losing speed on Oklahoma City's steep, mountainous highways with any sort of breeze other than a tail wind. If you're not familiar with Oklahoma, I'm being very facetious, as it's flat as hell. Our highway inclines are very slight, yet I lose speed and have to downshift in order to maintain. 3.21 with 33s on my '13 JKU 6-speed manual. I have no damn clue how people are okay with this, and my 33s have a 32" rolling height. I'm absolutely clueless as to how people even think it's okay with bigger 35s, especially considering it seems that most JKUs are automatics. It's not bad at all for off road or even city driving, but damn it's gutless above 60 MPH. About the only part of it that makes me happy is getting close to 25 MPG with my cruise set at 67 and a strong tail wind.
JK Newbie
Joined: Jan 2015
Posts: 39
Likes: 0
From: South Padre Island, TX
I have 33's...a few aftermarket items, notably the cold air intake. I was getting 20-20.5 MPG's unconsciously...not taking into consideration speed etc. I have a manual 6 and just in the last week, I've dropped to just above 18 MPG's. What gives? Weather has been consistent...driving habits haven't changed...what should I be on the look out for?
2007 3.8 V6 46,636 Miles
2007 3.8 V6 46,636 Miles
JK Junkie
Joined: Sep 2010
Posts: 2,539
Likes: 2
From: Tempe AZ
My 3.8L turd with 4.10's and 37's still averages 15 combined and 17 highway. That 17 only comes into play when I have my top and doors on though.....so never..
You should expect a 1-3 mpg loss realistically with that set up. Leave the airdam on the front for maximum efficiency
You should expect a 1-3 mpg loss realistically with that set up. Leave the airdam on the front for maximum efficiency