I believe Jeep's website has the option to check out gear ratio under the 'owners' tab. 3.71 should not have a problem, but any weight/resistance added to a Jeep that is already not aerodynamic will just increase the problem more. Also heavier tires have a significant impact, I have Nitto Trail grapplers and they are a drag on the road, wish I went with something lighter.

Also a programmer, i.e. flashcal, will help get everything in order for performance.

 

I wouldn't worry about it. Stock with a manual, I was getting 18mpg. With 35 and no other changes, it dropped down to 16.5 mpg. Today with 38s I am getting 13mpg. I can't wait to see what I get after I install the super charger . At this point there is no need to worry.

 

Thanks guys. Who needs a mechanic when I have all of you. I will look into getting a programmer and playing around with it. Next week I will be installing Gibson Cat-Backs. I see a lot of money being spent. Thanks again

 

Hey... I was helpful. or perhaps just a bit depressing.

 

Hey worth mentioning for anyone else who might be reading this. The biggest hit on your MPG will be the unsprung weight of the wheels. Even when people say 35's. I have seen rims 17x9, that range from 26lbs - 37lbs. Same for tires, 58lb for general grabber AT's versus 75lb falkens.

So, if someone says... I have blah blah blah power on 35's. It helps to know tire brand, size, and same for rims. Static weight aint that big od a drag as having heavier wheels.

Just sharing... Thanks!

 

[QUOTE Static weight aint that big od a drag as having heavier wheels.

Just sharing... Thanks![/QUOTE]

So true. We went from stock rims and 35" KMs to ATX slabs and 35" Nitto trail grapples and the milage drop by 2 mpg. Nothing ells changed. We have a 2 door with 4:10.

 

I'll disagree to an extent with the static weight not impacting MPG...when I put on 33's I was still seeing between 18 and 19 HWY, changed bumpers and the air deflector with the stock plastic bumper disappeared and my mileage dropped to 15-16 HWY. The unsprung weight will definitely slow acceleration a bit, and wider tires will also have a detriment to your fuel economy, but you're driving a slightly mod'd JK so obviously fuel economy wasn't your primary concern.