Am I going to regret 4.88s?? Help a gear noob out!!
11-05-2010 | 11:00 PM
#11
JK Jedi Master
Joined: Jan 2008
Posts: 11,463
Likes: 162
From: Austin <--> Colorado Springs
Open the Drivetrain FAQ at the top of this modified area.
Measure your tires (measured, not mfg's listed height!!) and plug the numbers in. You'll soon see that for an auto, you can pretty much disregard the "you'll have screaming high RPM's" advice...
Start reading a bunch of the other 1000+ threads asking this exact same question, and you will see that rpm's in the mid-2k's are where this engine likes to run, where it gives better performance, and contrary to what the 'screaming high rpm' guys will tell you, better mpg's.
Also, see page 3 in this one for a great explanation of the reasons behind the difference between auto and manual gearing.
https://www.jk-forum.com/forums/show...itude%29/page3
Measure your tires (measured, not mfg's listed height!!) and plug the numbers in. You'll soon see that for an auto, you can pretty much disregard the "you'll have screaming high RPM's" advice...
Start reading a bunch of the other 1000+ threads asking this exact same question, and you will see that rpm's in the mid-2k's are where this engine likes to run, where it gives better performance, and contrary to what the 'screaming high rpm' guys will tell you, better mpg's.
Also, see page 3 in this one for a great explanation of the reasons behind the difference between auto and manual gearing.
https://www.jk-forum.com/forums/show...itude%29/page3
11-06-2010 | 06:23 AM
#12
JK Super Freak
Joined: Jul 2008
Posts: 1,934
Likes: 0
From: Middle of no where
Ok so Im on the verge of ordering gears and Im back and forth on what size. Im back and forth between 4.88s and 5.13s. I have a 2008 JK X Auto tranny on 35inch MTRs. Im on the highway once or twice a week and theres always the potential for a trip down to like the jersey shore or penn state. Alot of people I know are saying go with the 4.88s because ill be rev'ing out like crazy on the highway if I get 5.13s. Obviously Long Island isnt that hilly soooooo the question is....
Am I going to regret 4.88's or should I get the 5.13s??
Am I going to regret 4.88's or should I get the 5.13s??
11-06-2010 | 07:16 AM
#15
JK Newbie
Joined: Oct 2010
Posts: 18
Likes: 0
From: O'Fallon, Mo.
Planman,
AWSOME information. Thank you for sharing. I will be upgrading gears soon too and was considering various ratios as well. Now Im set on 5.38's Thanks for the valuable information and un-biased rational factual based response.
AWSOME information. Thank you for sharing. I will be upgrading gears soon too and was considering various ratios as well. Now Im set on 5.38's Thanks for the valuable information and un-biased rational factual based response.
11-06-2010 | 08:36 AM
#17
JK Newbie
Joined: Jun 2010
Posts: 99
Likes: 0
From: Marshall,Tx.
So much misinformation. You would not be "revving like crazy" with an auto or a 6 speed especially with 5.13s or 5.38s there is a gear chart you can look at that will show you exactly the rpms you will turn with what tires and transmission.
4.88s would be great if you had a TJ, but the JKs motor is much better suited to 5.13-5.38 with 35s. I liked my 5.13s with my 33s (measured 32.1 actual) but I regret not having got 5.38s after running 35s a while now. You will regret like hell not going with a minimum of 5.13s if you plan on 35s. 4.88s are a total waste of money. You will be SICK for spending the cash on not enough gear.
4.88s would be great if you had a TJ, but the JKs motor is much better suited to 5.13-5.38 with 35s. I liked my 5.13s with my 33s (measured 32.1 actual) but I regret not having got 5.38s after running 35s a while now. You will regret like hell not going with a minimum of 5.13s if you plan on 35s. 4.88s are a total waste of money. You will be SICK for spending the cash on not enough gear.
11-06-2010 | 04:46 PM
#18
JK Super Freak
Joined: Jul 2008
Posts: 1,934
Likes: 0
From: Middle of no where
11-06-2010 | 06:55 PM
#19
JK Enthusiast
Joined: May 2010
Posts: 307
Likes: 0
From: Louisiana
With a smaller than stock gear on the end of the pinion, you actually reduce the stress on the pinion shaft, up until you grt so small you start making the gear smaller than the pinion shaft itself, then it weakens the pinion.
11-06-2010 | 06:56 PM
#20
JK Super Freak
Joined: Sep 2007
Posts: 1,502
Likes: 1
From: Columbia, IL
I run 5:13s and never regreted it. My opion on the gear thing is this. Many say 4:88s because this brings you back to a stock like RPM range. That would be great if the stock range would have been good to start with. Rubicons should have been equiped with 4:56s with 32's in the 1st place. 4:88s only get you back to mediocre. Why spend the money unless you are getting something worth while