Went to the store to pull the trigger on a set of g2 gears 5.38's and was talked out of them by four salesmen and the installation guy, not only that I had two other customers telling me I was crazy and that I would burn up the tranny or the gears themselves. It was like me against a mob of angry off-roaders.
There are a couple of things I am worried about, one it is a DAILY DRIVER, and two It does see about anywhere from 10 to 20 miles of highway driving a day, and finally it is a 2010 Rubi. WITH ONLY 3000 miles on it and don't feel like destroying it more by............... as some one put it on another tread NOT FEARING THE GEAR. sorry couldn't find the author of that one.
well just a little info its a 2010 RUBI unlimited with 35's and planning on moving up to 37's sometime soon. but I am having the front diff changed out so I thought might as well have the gears changed.

HELP, I don't want to have 5.13's and wish I would have gone with the 5.38's About to call and change the order.

 

I have G-2 5.38 with an auto, 37" tires and Dana 44's. I would have regretted anything less as the 37" tires put me damn near close to where I was stock. I am sooooo glad I went with 5.38. Just my opinion but I'm happy. My jeep is a daily driver and my gas mileage is the same as it was stock. You won't regret it.

 

I hope this helps you over think what you already probably know. This will drive you even more nuts. So enjoy
http://www.grimmjeeper.com/gears.html

STEP

 

find another install guy

 

THANKS GUYS,
I was a little scared, especially when even the installer pretty much refused to put them in because it would cause too much "DAMAGE" to my jeep, now to change the order and get those 5.38's thats what I wanted in the first place.
I read all the forums and seen all the calculators. Just threw me back when they refused to warrenty them and the install........ but that they would do the work if I still wanted them ....time to find a new shop. Thanks again

 

x 2 on the new installer

 

I would say 5.13s would be the way to go. If your ultimate concern is off road, then yes 5.38s.

Once you get 5.38s, the teeth contact is less, making it more prone to failure. I'm running 5.13s in my 30. Because of the increase gear ratio the teeth make contact at about 1 and a half to 1 and three quarters. If I had chosen 4.88s it would've been about 2 teeth making contact. So I am gambling a bit but with the way I wheel it should be alright.

I don't know many people running 37s with 5.13s (even with an auto) that complain of it being overgeared, but I have certainly heard people complain that the 5.38s are overgeared.

 

I have to say, before I regeared I read the posts from planman and thought he was extreme and that I wouldn't go that route, but now after having regeared I can say he is right and definitely seems to know his stuff. Thanks planman!!

I have 35's with and unlimited auto and I was worried about the same things you are. Mine is a Rubi with only 3000 miles on it now (even less when I regeared) and I did not want to ruin my brand new jeep. It is also my DD with a fair amount of highway miles each day.

I decided to go for it though and put in the 5.13s and boy am I glad I did. I also drove a jeep owned by the guy that did the regear. His has 37's with 5.38's and I can say I wouldn't do anything less than 5.38s if you are putting 37's on. The RPMs are the same if you look at the chart comparing 35's with 5.13s and 37's with 5.38s. I have not once felt like I am running too high of RPM's on the highway and I like to drive a little fast sometimes. I would go far enough to say that I probably could have gotten away with doing 5.38s with my 35's and been just fine but the 5.13s fit my driving style perfectly.

Sorry for the long winded post. I just wanted to help you out since you seem to be exactly where I was. I couldn't wrap my mind around what a regear could do for me. I felt like the 4.10s with the 35's was fine. Once I did the regear, then I understood.

Do the 5.38s and don't look back.

 

You're completely missing the boat here. Go with 5.38s if your ultimate concern is ON ROAD! You need the low gearing to stay in high gear with the auto transmission if you have oversized tires. You could run much higher gearing if your ultimate concern was off road. Even the stock gearing with his Rubi (4.10) would be more than adequate for off road, because of his 4:1 transfer case low range gearing. We aren't regearing these Jeeps for off road performance, we're regearing them for ON ROAD performance, and you need the lower gearing to overcome that deep overdrive in the auto trans.

And to the OP, the people at that gear shop have not kept up with Jeeping. They are wanting to do the same thing they have done with CJs, YJs, and to some extent TJs, and to pickup trucks for the last thirty years. In those vehicles a set of 4.56 gears is considered low. The JK is not an old pickup truck, or a CJ. These people that are telling you to use 5.38 gears are right, so I agree with you finding a new shop.

I put 35" tires and 5.38 gears in my 2010 Rubi when it had 800 miles on it. It now has 3000 miles on it, so I've had the chance to see how the gears work. I even did a 400 mile road trip on the interstate. 5.38 gears are just about perfect for 35" tires. They are perfect in the valleys, but not quite low enough in the mountains. I can live with that.

 

yooooooooo seriously go with the 538s you will be thrilled