FASTMETAL

i got 31's on the jeep with 3.55's and it feels great and has plenty of power but i can't believe how much gas milage i lost , i was getting average around town 16 now im just barely getting 11 mpg .. i cant beilieve there was this much of a drop,,, what gears would help? are 4.10's to much?,, mind you this is a DD,, i has the 8 1/4 in it,, any help would be great

ZachsXJ

3.73s or 4.10s I'd say go with the 4.10s for 31s and an autotrans

4.0cherokee

I am still running 3.55's It does between 1750 and 2k going down the road at 65-70. I am getting bad MPG but it is not becuase of the 31's. Long story which still isnt solved yet. I think I may have slowly found what it is, but another story for another time. I would go 4 10's. I will get them when i got to 33's

FASTMETAL

so does mine but i'd like to try to get that gas milage back up some more,,, oops i put this in the wrong section lol,, supposed to be under XJ haha

Dan91

Well, don't forget to factor in that extra travel of the larger tire into your gas mileage. New tire size to old tire size ratio multiplied by gas mileage=actual mileage. Unless you properly re geared your odometer to compensate already.