4.88's or 5.13's

AncientTrail

AncientTrail

New member
My rig is a 2012 JKU Rubicon auto with 4.10's and 35's. My use is 70/30.

I'm re-gearing tomorrow but have to decide which way to go. My question is, if I go with the 5.13's and decide to stay with the 35's, will I regret it in the long run and wished I had went with the 4.88's? I'm not concerned with gas mileage.

I go to Calico, Moab, John Bull, Sand Hallow, Utah and around here in Ridgecrest.

If someone has been down this road I would appreciate your input!

:beer:

< that is my jeep by the way
 
wayoflife

wayoflife

Administrator
Staff member
If you're not concerned with MPG, get the 5.13's especially if you have an auto. You would regret getting 4.88 - trust me.
 
JK_Dave

JK_Dave

Caught the Bug
Based on this, "I'm not concerned with gas mileage." I'd say go 5.13, but you probably wouldn't be sorry with either choice.
 
AncientTrail

AncientTrail

New member
wayoflife said:
If you're not concerned with MPG, get the 5.13's especially if you have an auto. You would regret getting 4.88 - trust me.
Click to expand...

5.13's it is then.

According to the charts it seems real close RPM wise but real world experience is usually more helpful.

Thanks!

:beer:
 
AncientTrail

AncientTrail

New member
DESERTDAD said:
So excuse my ignorance but is yours a 3.8 or 3.6??
Mine is a 3.6 and I am questioning the same thing.
Click to expand...

It's a 3.6 Auto.

I'm going to drive a club members jeep in just a bit that has been re-geared to 5.13's. Only thing is, his is a 3.8 auto but he's also on 35's like me.

Question: will the 3.8 be close in performance to what I can expect?

:beer:
 
2Cross

2Cross

Caught the Bug
Anyone know how often the 5.13s break when the 4.88s don't?

My buddy broke his 5.13s r/p twice (37" MTRs) before going to a ProRock 80 rearend. I went with 4.88s for this reason when I went with my ProRock 60 rearend.
 
AncientTrail

AncientTrail

New member
2Cross said:
Anyone know how often the 5.13s break when the 4.88s don't?

My buddy broke his 5.13s r/p twice (37" MTRs) before going to a ProRock 80 rearend. I went with 4.88s for this reason when I went with my ProRock 60 rearend.
Click to expand...

That's a good question?

The shop doing the work for me suggested 4.88's for that reason. Oh jeeze, more to think about LOL!
 
13_gecko_rubi

13_gecko_rubi

Caught the Bug
I have 4.88s in my rig. I'll admit I did 4.88 instead of 5.13 because it's my dd and I wanted to help fuel efficiency a little. Having said that I have never had regrets with the 4.88s and my 37s. The 5.13s I'm sure would have a little more pick up but the 4.88s work fine for 37s. So I'm sure on 35s it would be even better. But if you dont care about fuel efficiency and want best pickup go 5.13.

did your buddy break two r&ps with the stock engine? I realize the PR60 is high pinion which hurts a little on a rear application but still seems extreme to break two with stock engine.

Sent from my SM-G900V using WAYALIFE mobile app
 
2Cross

2Cross

Caught the Bug
My buddy that broke 2 R&Ps has a v8 and he's heavy on the skinny pedal.
Both times he was on the golden staircase in Moab. He hasn't broke the PR80 and it's been almost 2 years!
 
KingCopperhead

KingCopperhead

New member
For what it's worth I have a 2014 manual 2 door. I'm running 35's with 4.88 gears. The difference from 3.73 gears was incredible. Took it off road for the first time Sunday and it was a major difference. Easily crawled over things that I used to have to clutch and throttle over.

As for on road: I turn close to 3k rpm at 65mph in 6th gear. Gas mileage isn't great. Averaging 13-14mpg with a 50/50 hwy/Street mix. I think this gear set is perfect for a manual jk with 35's and from what I've heard from several other members, it works well with up to a 37" tire.

That being said, the automatic transmission is geared differently. 5.13's might be a better fit for you, especially if you don't mind taking a hit to your mileage. I'd also suggest a tuner to refine your shift points once you regear.
 
NFRs2000NYC

NFRs2000NYC

Caught the Bug
IMHO, 5.13s would turn pretty high on the highway....I don't know california speed limits, but in a place like NYC where most highways are 50 or 55, you'd be ok. If I lived in a place with 65-75mph speed limits, me thinks 5.13s would be a tad high. I had 3.21s and 33s on my last rig (horrible) and now have 35s on 4.10s and they are nice on the highway. Would be nicer for 4.56 or 4.88 in the city though. I am getting about 15 in heavy city, 18 highway, and my rig is pretty damn heavy (full width steels, 35s, carrier, skids, rock rails, winch, etc) Just my .02
 
wayoflife

wayoflife

Administrator
Staff member
2Cross said:
Anyone know how often the 5.13s break when the 4.88s don't?

My buddy broke his 5.13s r/p twice (37" MTRs) before going to a ProRock 80 rearend. I went with 4.88s for this reason when I went with my ProRock 60 rearend.
Click to expand...

2Cross said:
My buddy that broke 2 R&Ps has a v8 and he's heavy on the skinny pedal.
Both times he was on the golden staircase in Moab. He hasn't broke the PR80 and it's been almost 2 years!
Click to expand...

Ummm, yeah. As mentioned, that explains a lot. Is it safe to assume he was running a Dana 44 before upgrading to the ProRock 80?

Even with a ProRock 60, big horse power and a driver who likes the skinny pedal will break a high pinion r&p. In addition to be much larger in size, the ProRock 80 is a low pinion design which means it'll run on the strong side of the ring gear.

For most people running a factory motor and Dana 44's, a 5.13 will be plenty strong even with 37's. At least, it was for me but then, I'm just a mall crawler.
 
jeffj

jeffj

Caught the Bug
I'm running 4:88's with 37's and live in the hills of WV. It's not to bad, but it sometimes kicks into passing gear when it would be nice to have a little extra power so It would stay in the same gear. On flats I'm running 2800 rpm's at 70 mph. I have heard 5:13's are at 3000 so not a hole lot of difference. My gears are good for my type of driving about 90% of the time.
 
2

2011jk

Member
When I had 37" with 5.13's still wanted more , then a newer JK with 5.38's better, now with 40" need the :LS badly.
 
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