I have an auto 08 jk unlimited x. If I put 3.15's on or 3.73's on with 33's or 35's what should I expect from the shifting and how bad will my fuel mileage get?

 

3.21's?? i got 3.21's and will have 33's in about week!

 

If you run 35's your mileage is going to go down period.

Adding gears will make the Jeep more driveable on and off the road. Based on numerous threads MPG is all over the map based on location, driving habits, vehicle equipment, tuning, etc so don't expect to get an exact value of your MPG if you make any of these changes. Just consider the average relative change due to each mods.

The SEARCH button will expose dozens of threads on tire sizes, gearing and fuel economy. The FAQ will provide a great summary of this information.

 

what do i have stock? I thought the auto unlimited x comes with 321's no idea please school me.

 

If you would like to know what gears you have just take your vin number to a local dealer or email Jeep. They can provide you with a build sheet of everything your jeep came with.

 

If I put 33's on my jeep 2.5" budget boost, Do I have to regear? If so, to what? Will I need to get a hyper tech? Is it going to go below 10 MPG? It is a stock unlimeted X with an auto.

 

my 2 door auto with 3:73s and 33 tires gets 14 mpg highway.

 

i have 33 with 3.73 gears on my 08 auto. with factory tires I get about 18mpg and with 33s, i get about 15mpg. the shifting band was not that bad. At 65, rpm is about 2000. note: i also have a heavy left foot. lol

 

i have nitto terra graplers 295/75/16 which measure out on my steelies to be 33.4" and i am running a 6spd with 3.21's... i have had no problems with it since ibought my superchip which helped give me a bit more power/mpg's/fixed the speedo/tach and if you have an auto will fix the shifting points.... i am actually debating 35's right now but i would never regear for the 33's and my setup....

 

does that mean you press the brake & the gas at the same time?