J.morris

Just wondering what would be a good gear ratio to go with, I would like to keep decent fuel mileage, I'm not an aggressive off roader so I don't need anything super low, just pull my boats, a few other toys, and ride in the woods during hunting season...

Canvas

Need a bit more information, year model, tires, etc....
https://www.jk-forum.com/forums/modi...imited-213377/

J.morris

It's a 2012 and right now ive just got some 285s on it but I'm thinking about lifting it and probably gonna go with 35inch tires

Canvas

Well if you do not think you are going bigger than 35's you can do either the 4.56 or 4.88's. Look at the chart link on my previous reply which will show you why I recommend them. I will caution you on gears because I hate paying for things twice so when I regeared my Jeep I went with 5.13's because I knew that my next set of tires will be 37's.

Lift has nothing to do with gear selection, it does however provide for going with a bigger tire later on.

Hope this helps.

R/
Will

J.morris

Thanks, my jeep will still be on the highway a lot and I want to decent mpg as well as pull a load pretty good too

munir

I went with 4.56 on 35s and a 13 auto. Drives great on the road and is still plenty capable on the trails. However if you're pulling a heavy load often, 4.88 may be the better option

J.morris

I won't be pulling anything real heavy, the main thing I pull is my boat and occasionally my rhino during hunting season, I'm kind of thinking about going with a set of 4.10's but I'd like to get some input from someone running that set up before I do it.

mr72

Then bigger tires and lower gears are not a very good idea.

You will sacrifice fuel economy and available power both.

Jonathan_JK

I'm basically Running 34's and I have 3.73's. Around town I get 15 MPG and on the highway 55+ MPH its 18MPG. I don't Tow anything so no info to share on that regard.

Offloading I'm able to do the same stuff as the guys with 4.88's and I don't get high revs at 70MPH on the highway. 50 MPH I'm right above the green dashes in 4th gear. What people fail to understand 5th and 6th gear are overdrive gears your not supposed to have power in those gears thats why they are considered overdrive gears. 4th gear is supposed to be a 1 to 1 drive ratio. Most manufacturers still go by this guideline to date.

zstairlessone

Is it possible that the folks that design these things take tire diameter and torque curves into account when they put in diffs and select transmission ratios? You can get a 3.21 with 29" tires, a 3.73 or 4.10 with 32" tires, and my jeep, with the stock 32" KMs was peppy and accelerated nicely up some steep roads in the SoCal mountains in 6th gear (overdrive II?). I don't think putting a transmission into 5th and/or 6th should or does result in the vehicle no longer being able to accelerate (at reasonable speeds - not 100+ mph) in a lively manner as delivered. If that was the case Chrysler would have put 4-bangers and 0.50 sixth gears in these to up the CAFE ratings.

What guideline are you referencing?

They are considered overdrive because they are 'over driving' the driveshaft (spinning it faster than the crankshaft) not because there should or should not be power available.

Take a look at thrust curves for various gear/final/tire size combinations, that is where the story is. If I put 48" tires on my 4.10 diff'd 6 speed JK then sure I'm not accelerating in 5th or 6th. Heck I'm probably not accelerating in 3rd or 4th either and I will be burning up the clutch in first starting out, if I put the stock sized tires back on it feels like a go cart, pretty darn fun.