onsafari

I'm assuming you have a Rubicon so with the 6 speed I would say 4.88's would be perfect with 35's

If you have an auto I thinks it's a toss up. Not a big fan of 5.13's in a D44 since your ring gear is getting a bit weak at this point but I'm sure others will dissagree.

Evolution

For the 6 speed guys
5.13 and 35 inch tires
in over drive at 75MPH will be 3102 rpms

MBAR741028

Evolution, have you done any gears in the 3.21 ratio axles? I am trying to find out if the 4.88's I have are going to fit no one knows. If not any Idea of what parts I will need. Thanks

Piginajeep

that would be about what it was stock, at 75 mph.. if I remember correctly..

What would you do?

wayoflife

So, are you saying that you would recommend 5.13's with 35" tires? Like piginajeep, I will ultimately get my JK sitting on 37's but that might be a year down the road. Oh, and I have a 6-speed

Evolution

stock with the 6 speed 4.10 and 32s .
2712rpms at 75 and in overdrive

Jasson

:confused: This seems to be a big issue/question for a lot of JK owners. If someone who knows what their talking about could post recomendations for different situations it would probably help a lot of people.

4.88 & 5.13
35's and 6 speed?
35's and auto?
37's and 6 speed?
37's and auto?

What about this weekness issue that has been brought up with 5.13's? What's that all about? You can destroy gas mileage in almost any vehicle if you have your foot in it all the time, I'd also like know which gears are best for improving mileage or do they help at all?:confused:

Any help would get many thanks by many a JK owner.

DTCVTC

what about up grading your 3.21 do i need a new carrier?

onsafari

The strength issue on the 5.13 is due to the ring gear getting thinner as the ratio's go up. Also the contact between the ring gear and pinion gear becomes less as well. Typically you want at least two teeth touching each other. This was big issue with D30's and 4.88 gear sets. The pinion gear and ring gear only had one tooth touching making it very weak. On the front it's not as big an issue with the rear. I haven't seen a set of 5.13's in a JK D44 so can't say for sure what they look like. That's why I posted the question at the bigining asking for this info but nobody seems to want to answer.....even the guys that put them in.

SouthSideSteve

May I ask what you are using to run those #s? I too was thinking of 5.13s with 35s. And often wondered if they were too deep.


Stock on a 6 spd w/ 32s and 4.10 is roughly 2800 @ 75 and 3k @ 80. This is just eyeballin g the tach. I ask how you are getting those numbers so I can calculate then exactly.