Originally Posted by j_king

So I just got my Teraflex 2.5 coil lift and 35" Duratracs put on my new 2011 JK unlimited and love it!

However I can definitely tell I will need to regear in the future. Driving around the city seems fine but the noticeable change comes when driving on the highway. The lack of power (not that there was that much before) makes it very hard to maintain highway speeds without constant gear switching while OD is on.

I have noticed in a lot of the gearing threads people recommend to turn OD off with 35" tires if you haven't regeared yet. What does that accomplish and would that help with highway driving? Would turning OD off help with highway fuel mileage by maintaining a consistent RPM without the constant gear switching?

And just FYI my current gears are the 3.73 with LSD and it's an auto if that makes any difference.

Thanks for helping out the newbie!

Originally Posted by S3AWOLF

I get an average of 19.5 mpg with the stock 32" tires at 75mph and 2000rpm on the highway (OD on) what can I expect with 35" tires. I have a 2011 with 3.73 gearing and I live in Florida where it's flat for the most part with the occasional rolling hill, but rarely does the transmission downshift from 4th. Every vehicle I've ever owned including my last pickup truck has cruised at 75mph at around 2000 rpm. Call me crazy but seems like the lower the rpm the better as long as you live in a flat area like I do. If I go 35s and my RPM drops to around 1700RPM at 70MPH is that such a bad thing as long as I am in flat Florida?
I hear guys talking about their mpg going down to 12mpg on the highway and seems to me it's because they are running at 2500+ RPM or more. I guess I just don't have a lead foot and notice it like a lot of people.

I will eventually re-gear when I get the cash to do so, but tires have to come first and my hope is with a programmer I'll be able to get by as others have already suggested. I am also guessing that smaller and lighter 35 tires probably make a difference as well and could help.