Abdulla_6969

Hi Everyone,
I'm new to that forum, and its cool so far
I wanna ask a question regarding the Ring Pinion and its efficiency..
I'm having a 2012 JK and its perfomance was nice at stock, at cruising I can reach 115 Mph
At the moment, i've added the RC 2.5" Lift Kit and 33 ProComp Tires, acceleration is fine, but having problems with cruising (83 Mph Maximum @ 6th Gear)
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So far im OK with that performance
But im willing to go wild with 6" Lift Kit & 37 Tires..
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What's the difference between the 4.56, 4.88 & 5.13 Gears?
For the 6" Lift & 37 Tires .. Which gear can get me my performance back?
And does the performance get back, or it only gets better?
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NEED HELP, Any Experience or Feedback might be helpful guys,
and would be really appreciated
Thanks

h20squirter

115 MPH in a Jeep? were you being chased? I have driven lots of vehicles much much faster than this, but no way in hell I would drive my Wrangler that fast. If your running 3.73 or 4.10 gears stock then I wouldn't bother re-gearing until you go bigger on your tires.

Abdulla_6969

Lo0o0o0o0oL
Hi Squirter, honestly I can't drive a car without knowing its capabilities..
I was on a highway from my city to Dubai (60 Miles Away) so I wanted to give it a try..
I have a 2011 Audi A8 ABT, and never reached the 185 MPH only once..

Ya i'm willing to go up to 37's and 6" Lift Kit
I just need a 90 MPH for cruising at highways, thats enough for me
Should I go for the 4.88?

Nwapache

Welcome aboard!

There are a couple of things to consider; lifting your jeep 6" will affect your aerodynamics. For desert driving, you would do better to lift 2.5-3.5" and switching to flat fenders. Also, the lift kit you choose will impact how stable the jeep is at high speeds.
Once you move up to 37" tires, it gets MORE complicated as you increase the rotational mass of your tires, you need more horsepower to handle the speeds. Regardless of what gears you choose, spinning that extra weight will slow you down. Lastly, do you have an automatic transmission, or manual? That difference will affect your gear choice.
If I was building your jeep I would do the following:
AEV 3.5" SC or RS
Flat fender flares
37" tires of your choice
Axle sleeves and gussets
4:88 gear set (auto) 5:13 gear set (manual)

Your MPG, your acceleration and top speed will all drop but this set up will affect things the least. Good luck and continue reading and learning.

totdoc

I'd actually suggest the 4.88's on the manual as well. I just had 4.88's installed in my 2012 manual rubi this weekend, and it is back to it's stock performance of the 4.10's. I know that 5.13 was the sweet spot for 2011 and prior manuals, but the new engine seems to really hum along well with 4.88's. As an extra bonus, the teeth on the 4.88s are a little stouter than the 5.13's, which is also a good thing. I was really surprised how nicely the '12 manual handled 37's even on the 4.10's, to be honest.

Nwapache

Are you on 37's?

Delux2769

Lol, read the last sentence.

totdoc

What he said! And yes, I'm rolling 37's. To further clarify, I have talked to a couple other people who have regeared to 4.88 also with their manual '12, and they were also very satisfied with the combo. The other 2 I had talked to previously had 3.8 equipped Jeeps on 37's with 5.13's. They told me 4.88 felt perfect, even in comparison to their old Jeep. I don't know anyone who has a 12 manual with 5.13s on 37's, and when I asked a couple times on a couple forums, the only responses I got were from people with 4.88s. They seemed VERY happy. That is what sold me on trying the 4.88.

Also, when you look at the 2012 RPM/Gearing chart that has been posted on here a million times, the 4.88s on the manual get you back to almost the exact same RPMs as the stock 4.10s on the rubi. I was very pleased with the stock performance of the engine, and from my experience so far, it feels like I am right back where I belong. If you are rolling in a stock '12 manual rubi and you feel there is not enough ooph there, then maybe the 5.13's are for you...or a Hemi. The '12 pulls reaaaaal nice.