Umm, that was my point? Vehicles don't evolve for the sake of evolving. Things improve, and lowing the ratio was an improvement over the poor stock setup in the pre-'12 JKs.

FWIW, I gained 1-2 MPG by going to 5.13's with 33'' tires, and the power output is much better then stock. I'm right where I was after my lift, but before I went to 33's in terms of fuel economy, and better then stock in terms of performance. The only situation where I may regret 5.13's would be if I lived in Texas where the speed limit is 80 (IIRC), in which case I shouldn't be driving a JK anyway since wind resistance increases at the square of the increase in speed, and makes for one hell of a noisy, gas sucking drive.

 

Lol well I know why it's not running hott and if either way I can't use my over drive with the gear swap or without then im contempt where im at for the time being lol.....but I will say that a regear is in my future because although I know where the rpms are efficient at,I also know that the low end torque is very low so that's my main reason for wanting to regear....but I know overdrive is for highway cruising and you turn it off when your towing because if not run a risk of burning up transmission....but If regearing means Jeep wont bog down anymore then it's worth it, lower gearing is better...but I think it varies obviously so,and to each their own on how we all want our rigs to drive, im more on the highway than off-road and I need higher gearing rather than super low gearing but I know that im gonna sacrifice a little because there's no all around perfect gear ratio.....but I do appreciate y'all arguing and letting me see two very different perspectives on a subject that is subject to change varying by opinion and terrain lol..but the OP wants fuel efficiency, so I think if your on the highway more like I am, higher gearing 33 inch tires, better intake and exhaust and a programmer less aggressive tires, and a lighter foot too...lighter bumpers lighter rims....but in my mind you can only make a brick shaped vehicle on big tires as fuel efficient as possible, build it to suit your needs.....

 

I just changed my already order 4.88 to 5.13...
Later I will be able to tell if I did a right choice...

 

Did I say that? No I didn't. I said I took your advice and went with 5.13s and it was a mistake.

 

Thank you for finally admitting there is no one size fits all answer instead of flat out arguing. That is my point! Btw, wasn't zig ring the praises to the jeep designers, just saying their design teams have significantly more knowledge, experience, and resources at their disposal than those of us one here.

 

I was just looking at the numbers, and your version of 2+2=4 doesn't quite add up. See if you can point me at my error.


(using 36" actual for your 37's, tuner/tb/kn not factored in, modify if needed)

Original setup -
3.73's with 36" tires
1682 @ 70
2437 @ 70 OD/Off (assuming you were driving od off 100% of the time?)
= 17 mpg freeway

New setup -
5.13, 36's
2313 @ 70
= 15.5 mpg freeway

Sooo, the way it reads is that lower freeway rpms hurt your mpg's?

Why is it that you feel 4.88's will improve the mileage?
4.88, 36's
2201 @ 70

By the numbers, losing 124 rpm lowered your mileage by 1.5mpgs. So what is the expected result of lowering the rpms yet another 112... ??

 

Lots of items have "Minimum requirements", "Recommended" tags and things suggesting better "Performance". That's exactly how I built out the charts. I personally wouldn't recommend that anyone choose a new gear set and land in the yellow area of the chart data in the FAQ. At the same time, I would say if you bought a larger set of tires and landed in the yellow area of the chart, probably not to go out and get a new gear set and I'd live with it. In other words, there are situations that are less than ideal that I would find acceptable, and a lot that I wouldn't if someone is going to have their differential cracked and have a new set of gears installed.

As for the Chrysler engineers, they need to deal with constraints the rest of us don't. They need to use bin parts, have broad appeal, satisfy the bean counters and make sure the soccer mom is happy. If I'm taking a cue from anyone at Chrysler, it would be the Mopar design team and what they do with their talents and skills without the same constraints as the engineers who need to serve the broad market. That said, the resources we have as the end user of a JK are far greater than those available to the engineers as we don't need to cater to the whims of anyone but ourselves, and sometimes of course the spouse.

 

I'm glad you think you know how fast I was going and exactly how many RPM my motor was turning. That's the problem with some poeple... they think they know what they are talking about but really don't... where is that flippoff thingy? Oh damn, wrong forum.

I think I'm done here as there seem to be far too many not willing to listen to reason, even when presented with facts.

Scouts Out!

PS, Jpop. Give me a shout next time you are in the DFW are and I will show you what I am talking about. It's driving 30 thru Ft Worth at 65ish, OD on, no downshifts. There is adequate torque to do it and I wouldn't mind showing you. Then maybe a meal at tilted kilt or redneck heaven. Plan, you're invited too.

 

I'll drop you a note the next time I'm down that way. It's always a packed week as I have a lot of dirt to cover while I'm there. Always seem to bring the snow when I'm there in the winter months and Texans could use a lot more practice driving in it.

 

Ohh man I hate hate hate driving on 30 and 35...I grew up in ennis bout 40 minutes south of Dallas,ohh man if you want some great food check out marionos,I think its off if skillmen