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Discussion Starter · #1 ·
getting my gears done next week on my 08 jku auto.everybody recommends the 5.13 with 35's but how is the drivability how are they on the highway or around town looking for real world comments from people with the same set up thanks tom
 

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Just doing the math here, but with an auto and 5.13s on 35" tires you'll be spinning just over a 100 RPMs LESS on the highway than a stock Rubi on 32" tires with a manual trans. In other words, you'd be spinning nearly stock numbers--though still lower than stock.

That can't possibly be bad for "drivability." Otherwise, every pre-2012 Rubi owner with a manual trans and stock 32" tires would be unhappy. In fact, for a pre-2012 auto on 35" tires, 5.38s would be closer to the stock Rubi numbers, though my recollection is that it's hard to get those into the D30 fronts.
 

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Discussion Starter · #4 ·
radical motorsports on 17 thats were i bought the jeep
 

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Discussion Starter · #5 ·
i want to hear from the guys running this combo 08 jku auto 35's 5.13
 

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Seems to be quiet on this topic . . .

I'll chime in again, despite not actually having the set up you're asking about.

Bear in mind that the fact that it's an 08 and a JKU doesn't really matter--2007, 2008, 2009, 2010, and 2011, and JKs versus JKUs, are all going to have the same specs insofar as engine and transmission are concerned.

This guy runs 5.13s in his 2011 JK on 33s, and he ran the 5.13s on stock 32" tires before that. Check out his post here, where he says:

I have 5.13's and 32's, and it works perfectly. All you need is a $150 AEV Pro Cal to fix your shift points. You need at LEAST 5.13's when going to 35's. I would recommend 5.38's. The 3.8 bolted to an AT in the pre- 2012 JK with 5.13's is perfect for 33's, and will work well with 35's.
(Emphasis original.)

The next post down is rics1997, who put 4.88s with his 33s in a 2010 auto, and he says:

I have 33's and was talked into 4.88 and wish I went to 5.13's now. 4.88 is great though but for towing, I wish that I had 5.13
Finally, you can also check out JK-Forum's FAQ here, which has this to say about going to 35" tires:

Q: What gear ratio should I be running with 35" tires?
A: In order to bring your Jeep's performance back to stock, you will need to run 4.88 gears with 35" tires. However, if you are looking for a little extra power, you should consider getting 5.13's. This is especially desirable if you have an automatic transmission.
(Emphasis mine.)

Hope that helps.
 

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While you're at it, you might as well run 5.38 gears. The 3.8 is sluggish anyway stock. If you're running 5.38's then you'll be ahead of the game. They are available for both rubi and non-rubi JK's now.
 

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Seems to be quiet on this topic . . .
Finally, you can also check out JK-Forum's FAQ here, which has this to say about going to 35" tires:

(Emphasis mine.)

Hope that helps.
Does that still apply to 2012 JKUR on 35s? Mine came with 3.73 and it's city performance/hill performance is "meh" at best, but on the freeway (flat) it has no problems. So I've been debating a regear.
 

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Does that still apply to 2012 JKUR on 35s? Mine came with 3.73 and it's city performance/hill performance is "meh" at best, but on the freeway (flat) it has no problems. So I've been debating a regear.
No. Totally different gear ratios.

Pre-2012s like the 2008 auto owned by the OP should use this chart. By contrast, you should use the chart attached below. The charts are quite different, so it's important to look at the right one.

For a 2012, it looks to me like 4.56s or 4.88s would be the best choice for 35s regardless of whether you have a manual or an auto. 5.13s or 5.38s--while good for a pre-2012 auto on 35s--would be quite high for either a manual or auto 2012 in my opinion.
 

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No. Totally different gear ratios.

Pre-2012s like the 2008 auto owned by the OP should use this chart. By contrast, you should use the chart attached below. The charts are quite different, so it's important to look at the right one.

For a 2012, it looks to me like 4.56s or 4.88s would be the best choice for 35s regardless of whether you have a manual or an auto. 5.13s or 5.38s--while good for a pre-2012 auto on 35s--would be quite high for either a manual or auto 2012 in my opinion.
Sorry for bringing up an old thread but, does the 2012 chart apply to 2014's? I'm trying to figure out what gears are necessary for 35's for a 2014 JKU Auto
 

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yes the 3.6 has not changed since it's first use in the Wrangler in 2012, other then the modified head but that has no bearing on the gear charts. Hp and torque remain the same at the same RPM values.
 

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yes the 3.6 has not changed since it's first use in the Wrangler in 2012, other then the modified head but that has no bearing on the gear charts. Hp and torque remain the same at the same RPM values.
Thanks. So a 2014 Automatic with 35's would need 4.56 gears?
 

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3.73's at best which means 4.56 is probably the way to go, or even 4.88 if you don't drive much highway.
X2. With proper gears your power will be good but your fuel economy is going to fall and your top end speed will be effected as your probably already aware of. If you re-gear and plan on selling the Jeep in the future it may not hold the resale value as well or might be difficult to resell unless of course you find another Jeep'r who plans on using it the same as you did. There is also the huge difference in price when you get to 35 in or larger tires and wheels the cost is huge and then there's the extra fuel you will need to turn those big boots. Good luck with your project.
 

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I have 513's on my 2013 and 2009, with 35's
Great improvement for day to day driving.
I run 35's with 5.13's on my 2012 6sp also, The thing is a torque pig!! Love it!
 

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I RUN THIS COMBO AAND AM VERY PLEASED WITH MY SET-UP. My jeep readily takes-off from a stand still. The powerband is seamless with my G2's 5.13's. I easily cruise at 60-62, and my gas mileage is vastly improved over the stock gears. I can run 70 with no hassle; however, my jeep is a cruiser. Therefore, 60-62 is just fine with me.
 
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