somewhereinla

easy, if you were doing 40mph and your friend recorded 50mph, a 10mph difference would be 20%. so if your average mpg is 11mpg, then your reel consumption would be 11+(1.1x2)= 13.2

magnumbob

That sounds about right. If your Jeep's speedometer was originally calibrated for the stock 29.3" tires with a circumference of 92.01", you would have to multiply by approximately 1.20 (or add 20%) to compensate for larger circumference of your 35's (109.90")
If you have a Rubicon that came with 32's, it works out to around 10% to compensate.

codcape

Thanks for the Math lesson...I plan on a chip and exhaust, I already added the Cold Air System...

I use to get 10.7 around Town in my H2, so 13 plus is great, guess Ill ride the Harley if I want to save on gas....

jeep329

17.2 here... all city no highway. Added a 2.5 lift, winch plate, winch...no change. It's my opinion that the single biggest contributor to loss of milage is tire size...

Bacon

codcape: are your "Nitto 35's" Mud Grapplers by any chance? if so, you're going to get horrible mileage simply because of your tires. those are next to boggers in terms of weight and gnarliness. if you switched to an a/t or even a milder m/t I bet you could get close to 16mpg. just a thought....not actually suggesting you switch tires, just pointing out that the serious aggressiveness of those tires are really hurting your mpg. I'm guessing your H2 had the stock bfg a/t's?

codcape

I have Nitto All Terrain Grapplers...not the more aggressive Mud.....The Tires are awesome, and very quiet....I think that the Speedo reading being off by 20% is causing the false reading...does anyone know what I need to do to correct the discrepency by changing the speedo gear or??

Ge99ne

I believe the hypertech max energy will let you set the correect tire size for your jeep'uter. No gear swapping anymore with tone rings.

heatinajeep

19.2 ish on highway.

18 ish in traffic

08 rubicon

jkkat

Usually get about 15 unless we are wheein then its just hellish down from there, but then i do have all this extra weight that is in my signature.

HappyCurmudgeon

As was said above, nope no gear changes to correct speedo on the JK, it is all programming in the computer now. Accupro, or Hypertech make programmers that can be used to correct the speedo. Jeep dealers can correct up to 32"