1brownJKU

I have a 2013 JKU with the 3:73 gears. I am running 285/75 17 Goodyear duratrac tires. I hear on different forums about gas mileage. Now I didn't buy the jeep because of gas mileage but I hear about 16-17 mpg on 35's . My local 4 wheel parts guy has the same jeep on 35's but a 2 door and gets 16. He states he drives the shit out of it. I try to keep mine in the eco range and I get 12-13 around town and 13-14 on the hwy at 65-75 mph. So are these other people crazy or is it me?

Cutman

I'm not lifted and I run 3.21 gears with stock 17" wheels, but I read these threads all day and that sounds low to me. Why? No idea.

14Sport

Did you reprogram tire size into the computer? If you didn't then you can't go by the speedo or the odometer as they are incorrect as the wrong tire size is being used in the computer calculations.

1brownJKU

14sport

The jeep had originally come with the steel wheels and the dealer put a 2.5" terraflex with the 17" 5 spoke jeep wheels they told me they corrected the tire size but I have had no change in mpg.

14Sport

Well if you have a GPS you can check your speed against it to see if they did. Also, the road side rigs that display your MPH would work too. I have 35s and a 2.5" lift with 3.73s and I get 15.5 MPG according to the lie-o-meter.

1brownJKU

The dealer advised me above 60 mph the speedometer would not be accurate and that is normal for oversized tires. Didn't make sense to me.

Rubicon91

So first off your dealer has no clue. If your speedo is off when going over 60 then it is going to be off going 10. What probably did not happen is they didn't use a programmer and recalibrate for your lift and tires. If you have a manual you really don't need to but your speedo will be off. If you have an auto definitely need one as your shift points are off. Buy an aev procal and you are all set. But when taking back to dealer you will need to reset so they don't zap your procal. As far as mpg I avg between 14-15mpg with 35s and 4.56 gears in town. Highway idk yet first trip tomorrow curious to see. Hope this helps.

14Sport

You're right. That doesn't make sense. You can dial it in as accurate as factory.

Tooadvanced

Hear it all the time too and I think ppl r full of it. I always hear these stories of guys who run 37's with full size spare and steel front and rear bumpers with skids and a winch that swear they get 18-20 mpg with 5.13 gears and 4 friends and a dog in it. Cough cough bull sh*t

1brownJKU

Thanks for all the info going to order a programmer.