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Modified JK Tech Tech related bulletin board forum regarding subjects such as suspension, tires & wheels, steering, bumpers, skid plates, drive train, cages, on-board air and other useful modifications that will help improve the performance and protection of your Jeep JK Wrangler (Rubicon, Sahara, Unlimited and X) on the trail.

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Gears! Gears! Gears!

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Old 12-10-2009 | 05:33 AM
  #1  
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Default Gears! Gears! Gears!

Ive had these 35's running for about two months now and i cant stand how sluggish this thing is. i need to know what gears i should throw in it and why. i know the talk is 5:13 but is my highway drive shot? Would 4:11 be better?

automatic
4dr
CIA
Exhaust
Old 12-10-2009 | 05:46 AM
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Nope. Won't even put you back to stock. 4.56 maybe, 4.88 at least, I'd say, to be worth the money. 5.13 is the way I'm gonna go.
Old 12-10-2009 | 05:47 AM
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Check this out:

Old 12-10-2009 | 06:41 AM
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as mentioned, 5.13's will give you the power you're looking for but, 4.88's will get you back up to stock performance.
Old 12-10-2009 | 06:46 AM
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Not sure about the auto's....but with my 6 speed and 35's, i wen't with the 5.13's. Even with the 4.10's stock i couldn't use 6th gear, and 5th was a mutha even in flat nebraska, goin down I-80 with a tailwind.

The 5.13's now allow me to use 6th gear, in a headwind, going uphill, with the backseat loaded, seriously, i'm not kidding. And at 75 i'm running 3200 rpm....not that bad at all. Go with the 5.13's atleast, and with the auto, i would really think hard about the 5.38's....unless of course you can opt for......a new HEMI
Old 12-10-2009 | 07:10 AM
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Why 5.38 on a Rubicon vice 5.13?

Originally Posted by planman
With an automatic and 35s, go absolutely as low as you can (5.13s with a non-Rubi and 5.38s with a Rubi).
Old 12-10-2009 | 07:18 AM
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Becaue rubicon has a dana 44 up front and will except the lower gears on a dana 30 which is what comes on everything elese 5.13 is the lowest you can go. I have 35's and 4.10 and it is not horrible but do not spend money to regear to this you will be unhappy.


For those running the km2 35's and 5.13 can you tell me what rpm you are running at 70 with an auto thanks.

I am looking to regear and would like to be about 2500 rpm at 70
Old 12-10-2009 | 08:16 AM
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Oh ok...im with you on the 4.1 gear set. I'm going 5.13's here in a week, but I have a manual.

Originally Posted by Alf1096
Becaue rubicon has a dana 44 up front and will except the lower gears on a dana 30 which is what comes on everything elese 5.13 is the lowest you can go. I have 35's and 4.10 and it is not horrible but do not spend money to regear to this you will be unhappy.


For those running the km2 35's and 5.13 can you tell me what rpm you are running at 70 with an auto thanks.

I am looking to regear and would like to be about 2500 rpm at 70
Old 12-10-2009 | 08:28 AM
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I'm another with 35KM2s / Auto / 5.13s

Make sure you get an AEV pro-cal or something to reset your shift points, and I've been extremely happy so far with my gears.
Had them about 1500 miles.
I usually cruise about 75 or so on the freeway and truthfully don't pay much attention to the rpm's.
Old 12-10-2009 | 08:28 AM
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Originally Posted by Scooter Scott
One question that I have always wondered...on that chart is the size of the tires the ACTUAL size or the size that the manufacturer lists?
I'd assume actual tire size. They vary so much from manufacturer to manufacturer that this would only be the logical manner to display accurate data.

Whoever put this chart together probably just recorded their RPM's with whatever measured size tire they were using. Unless they used their tire size as a starting point and used math to extrapolate, then it would vary on their tire manufacturer if they didn't actually measure...



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