hey guys, im still new to the forum and i have a question i would like to ask. i have a 2010 unlimited rubicon, i have put a 6" skyjacker lift and i have 35" tires, since then my fuel mileage got real bad and i understand this happened because i ran bigger tires. If i regrear will this help bring the mileage back down? i was thinking of changing to 5.13 ratio because i plan on running 37s in the future, will my differentials be able to handle the bigger gears? and will they affect highway driving? Thanks for the help


Matt

 

Rehearing will make the jeep a lot more drivable and should help with the mpgs. But don't except to get much better mpgs. You are driving a jeep

 

Yes being that you have a Rubi, your axles will be fine with the 5.13's, and will help restore the lost power and economy. I would also have some gussets welded on to beef up the front axle

 

What tires, what was your mileage before, and what is it now?

 

Just got back from Yellowstone (1300 mi.) and averaged 15.9. Thinking he has a newer Jeep it's probably better on 35's" with 4:10 gears.

 

Thanks guys much appreciated, I am running Mickey Thompson baha claws, I used to get 14.5L/100 km and now I am getting almost 18L/100km. I've talked to people locally and they said I can not run 5.13 but I need to ask people who have actually experienced the gear change!!

 

What did he say?

 

Two different people said that I will blow up my housings and that I wont be able to drive on the highway because I will be revving to high!!

 

Is it city/highway combined? That's a 3mpg drop, which is not too crazy, especially for the aggressive tires you have. Yes, you could run 5.13 gears, but personally, I would just run in 1 gear lower than you would with your stock tires at any given speed/gear. This will give you about the same rpm as regearing at the diff. And having 6 speeds on your manual transmission, you have way more options to fine tune your rpm's and gearing. Regearing your diffs will do the same, but at much higher cost + sacrificing r&p strength.

 

Someone at my local club said he can't drive 70 with 5.13's and 35's because it rev's too high. According to the gear calcs on the web, it should be turning about 2450 RPM. what are others JK's turning at 70 with 5.13's and 35's?