Ways to improve mileage in a JKU?

[Idahoan]

I think most vehicles are pretty consistent. The driving habits are usually the difference. In any vehicle, I get 4 to 8 mpg better than my wife.

I normally get 19 to 21 hwy in my 2013 JKUR w/ 34" 10 ply tires and an Ursa Minor top.

 

[aristobrat]

At 70mph, my rpms are just a hair under 2700, would it be stupid to assume 35's would get my rpms down a bit and possibly increase mileage slightly?

Bigger tires do lower RPMs.

The usual problem with the pre-2012 JKs/automatics/35/stock gears (even 4.10s) is that the bigger tires lower the RPMs so much that at interstate speeds the engine is running under the power band. So anytime you give it gas, it has to downshift, which quickly kills the MPG.

I'm not sure if you've seen this chart, but for my 2010 auto, it was pretty spot on. Just remember to use the actual physical size of your tires. i.e. my 35" BFGs measured 33.75 when mounted. Going 60-65mph, with 35s/5.13s, on 300+ mile trips trips through flat'sh areas, I'd average in the high 19 mpgs.

 

[Kmrtnsn]

The 285s equate to a 33" tire, so they are not "big" compared to those running 35"s and small for that gearing. I am currently running around the West in our JKU, running stock KM2 32" tires turned by 3.73s but am carrying extra fuel, water, gear, and have a MRBP Off-Camber Fab roof rack and basket. We also have a 2.5" lift, which combined with the basket and baggage, isn't helping the aerodynamics. Yesterday we suffered our worst mileage of the trip, averaging 13 MPG driving into the wind from Gallup to Flagstaff at 74 MPH.

I didn't buy this rig for the mileage and think that considering the load and configuration that my mileage was right about where it should have been.

 

[Hilldweller]

What size are your wheels?
If you have 17s, try Toyo's Open Country AT-2 Xtreme in a 285/75-17
http://www.treaddepot.com/tire/352790.html
A bit more circumference without much weight.
Unless you don't need tires....

I had these on the PW that came stock with 285/70-17 and 4.56 gearing. Helped a bit but nothing can really help a PW with mpg.

 

[Septu]

I have a feeling I'll be getting rid of this thing by next spring as I really want a teardrop trailer but it would be painful towing one with this current setup. I'm just not sure that a newer one would be that much better either..

I have 2 trailers M101 and a Little Guy TD... my 2012 is towing either with zero issues. I'm not always the fastest up the hills... especially the steep mountain passes, but I get up them just fine... and it's rare that I'm that *** that's towing a rock up a hill while going half the speed limit (can usually hold 80/90 kph).

 

[N2Jeeps]

I gained about 3mpg after getting rid of my Gobi rack. Now I use a Rhino Rack Backbone system that has a Pioneer Tray that comes off easily. Way quieter also!

 

[Kmrtnsn]

I gained about 3mpg after getting rid of my Gobi rack. Now I use a Rhino Rack Backbone system that has a Pioneer Tray that comes off easily. Way quieter also!

I'll be removing the MRBP basket as soon as we return home, until the next expedition. I have been toying with the idea of converting a Yakima basket (narrowing it) and running it alongside my Skybox 16 we use on our Subaru.

 

[zigsrig]

Maybe I am lucky, but FWIW I'm getting 19.2 on the display after my lift and tires. Thats for the last 800 or so miles that includes my commute (11 miles of bumper to bumper) and 3 trips to the Colorado high country for some exploring with 4 people and a dog in the Jeep.

Maybe its just the cool color? :sombrero:

 

[Septu]

I gained about 3mpg after getting rid of my Gobi rack. Now I use a Rhino Rack Backbone system that has a Pioneer Tray that comes off easily. Way quieter also!

I guess it depends on what you want to carry... it has a max load rating of 264 LBs. I couldn't put my RTT and sleep up there... let alone have a 2nd person in the RTT.
http://www.rhinorack.com/en-us/products/roof-rack-parts/kits/backbone-3-base-mounting-system_rjkb1

 

[kojackJKU]

The gearing is the main problem with your milage. I am running stock 3.73s with 285s and drive 100kph and get 12.2L/100kms. My setup works great on and off road. I am adding a bajarack UT after taking to RSB. He said he maybe lost 1 mpg with adding the rack. The UT is very low profile so when not loaded it does not hold up too much wind. The other option is the surco removable option. but that cuts down on carrying abilities. I may want to run a RTT. But in your situation gear is all wrong. I was going to change my gears but decided my milage is more important than more grunt. RPM = Less MPG. ALWAYS

 

[Hilldweller]

More MPG musings.
Altitude matters. I always get much better mileage at higher altitude.
Ethanol matters. I always get much lower mileage with ethanol in the fuel.
Rolling resistance, wind, hills, weight of vehicle

 

[libarata]

Better intake, exhaust systems would help. Also, slowing down.

 

[Hilldweller]

Better intake, exhaust systems would help. Also, slowing down.

Driving downhill helps too...

 

[libarata]

Driving downhill helps too...

With just an CAI, and drafting behind Semis, I received 30mph in my Frontier a few dozen times.

 

[Hilldweller]

Yeah, drafting helps too. I did that on our last roadtrip until the trailer I was drafting in eastern PA blew a retread and the Jeep got blasted with highway rubbery.
It was downright scary.