hdvoodoo

I have 09 rubi and I am running 37s, will 538 gears help my gas mileage or just my torq? Really
can't afford for mileage to get worse.

jesse0376

i have a 2010 jku 6spd with 37s and 4.88s and the gears hurt my mileage a little but i do have better torque.

ronjenx

Have you reprogrammed for the bigger tires? That will show you the correct gas mileage.

Once you reprogram, you have to decide if you can live with the performance as it is with the 4.10 gears.

hdvoodoo

No I have reprogrammed. Honestly didn't think about doing that first.

livin

do you have a manual or automatic?

I had a manual 09 Rubicon JKU on 37's and yes I wanted more power but not enough to regear from the 4:10's. I got about 15 mpg on average.

JPop

Really need to fill in a lot of blanks here. The speed you drive, the terrain you roll over, transmission type and highway/city split.

Markdsv

2010 Sahara unlimited, just installed 5.13's + superchip on 33's, great improvement in torque still gussling fuel, not to worry as I fill up my tank for 20$US

I am running the 93+ tune though, you could opt for the economy tune......... don't know the answer though. (superchip is a must as you need to adjust your transmission changes and ODO)

CJ7nvrstk

Well ya. That's way too much gear for the tire at highway speed. You would likely notice an improvement in mileage with taller tires. (35s-37s) That would bring your highway rpm down closer to the range intended for better economy.

JPop

A 2010, automatic transmission, with 5.13s and 33s will run nearly identical rpms as a 2012 automatic with stock tires and 4.10s of a previous model year with a manual transmission with stock tires at highway cruise speeds.

That would be a statement of fact.

Markdsv

I agree....but highways here....don't make be laugh..indeed not or very limited. So not very high speeds just too bumpy. Also I have 35's as well and the superchip takes nicely care of tuning my transmission to gearing and tires.