Looking into regearing my 07 X w/6sp Man from 4:10 to 4:88 or 5:13's. Currently running 3"BD lift with 35" Procomp MT's. Been reading about the D30's braking a bit with the 35's (Daily driver with occassional wheeling fun w/jeep club).
1. I want to put in ARB air lockers in so do I need to upgrade the front axle to a super 30 kit or ?
2. Being a daily driver, I think the 4:88's will be better, does anyone have any experiece either way?
I would love to put in a D44 but that is a lot of $$$.

Thoughts, experiences, good technical data much appreciated.

Cheers
Mike

 

With the JK extra weigh I'd go 5.13s, even thoughit makes the d30 even weaker. ARB or an OX is a good choice. The "super 30" kit won't work with your JK d30, nothing is avalible yet, plus its going to usually be the u-joints that break. 35s are the very limit to any d30.

 

Why does changing the gears to 5.13 make the D30 even weaker?

 

Fewer teeth on the pinion gear to maintain the low ration. Larger diameter gearsets will have more teeth on the ring, and in-turn more on the pinion + the gear surfaces are wider and maintain the same ratio. More teeth on the pinion gear = more surface area in contact = stronger.

 

So 5.13's have fewer teeth therefore less suface= weaker? Is that right?

 

In theory, yes. It will also depend on the "pitch" of the teeth. Here are soe tooth count numbers for the Dana 44 for comparison:
Ratio Teeth (ring gear/pinion gear)
3.07 43-14
3.23 42-13
3.31 43-13
3.42 41-12
3.54 46-13
3.73 41-11
3.92 47-12
4.09 45-11
4.10 41-10
4.27 47-11
4.56 50-11
4.88 44-9
5.13 41-8
5.38 43-8

 

Appreciate the feedback. Still debating on the lockers. Much $$ for minimal use, but damn, it would be nice to have (look fellas an air compressor, pssst, pssst, locked unlocked).

 

dropping that much money on an ARB and gears might make it worth it to go to a dealership and get a price on a Rubicon spec D44. You might be surprised. And I'm sure there's some ranger/tacoma/S-10 driver out there on ebay who's looking for a solid axle to swap into their vehicle if you needed to gt rid of a D30 after replacing it.

 

You should be able to find one for less than $1400. You can then sell or part-out the 30. THat's what I am doing. According to the computer my 44 should be here tomorrow...we will see.

 

I have 37s with 5.13 gears and auburn lockers front and rear on my X. It has a dana 30 in the front and a 44 in the rear. I wheel blacks all day long and this setup seems to work great for me. Plus i drive this jeep everywhere and it runs and drives great.