I mostly use my jk on the road and I pull a trailer a lot (my rzr). With the rzr and trailer it pushes the limit on towing capacity. So I would like to regear to get more performance just driving around and during towing. I have the 3.8L auto currently with 33's, and most likely going to 35's with the next set of tires. So I've don research and I can't decide between 4.88's or 5.13's. Please need help in deciding. Has anyone had similar experiences?

 

i really think you'd be disappointed with 5.13, I have 5.13's but I've got 37's and I'm not sure that maybe I should have gone with the 4.88's


Matthew

 

You have more power and better transmission gear ratios than he does.

 

You can't compare your 3.6 6-spd to the OP's 3.8 auto, just confusing the issue.

OP, you didn't mention if you have found the charts in the faq's? If not, do so. If so, go back and plug in the numbers again. 2500 rpm at freeway speeds seems to be a good number to shoot for, for most people. (depending on specifics of area, driving style, specific build, etc.). 5.13 will be ok with 33's until you get the 35's. And when you have the 35's and are pulling the trailer, I think that you just might kick yourself for getting 4.88's.


I went from 3.73 and 32's, to 3.73 with 33's, to 5.13's with 33's, to 5.13 with 35's. Then swapped in a front d44 and upgraded to 5.38's with the 35's. And now sitting on 37's with the 5.38's. Just my opinion, but for my use/needs, I liked 5.13 with 33's and 5.38 with 35's the best.

 

I just picked up a set of 5.38's (having them installed next week). Right now I'm running 35's, but will be going to 37's when they wear out. For me the decision was pretty easy for my uses. Good luck

 

Can you describe your setup because I've got the 3.6, the factory non-rubicon transfer case with dynatrac's and 5.13 and I can't imagine 5.38's

Matthew

 

I can speak from experience. I moved from stock to 35" Duratracs (which are really like 34"). The Jeep wouldn't stay in OD on the highway which was unacceptable to me. I did my research and knew that I might eventually move up to 37s so I went with 5.13 gears. The Jeep performed well on 35s with these gears. I have since moved up to the 37s and the 5.13s seem to still be performing fine. In fact, my gas mileage has improved slightly (1 mpg) since moving up.

I have the 3.8L and auto. It is much slower on the 37s, but it's acceptable.

I wish I had the spare mod money to keep upgrading the gearing each time, but it cost $1200 to go from the stock 3.73s to 5.13s. I only want to do that once!

 

35" Toyo MT's, 3.8l engine, and auto trans. I'm going to 37's when the 35's wear out. My highway miles only consist of weekend drives to the lake or trails. Even "if" these turn out to be a little deep, it's no problem with how I use my jeep. The difference between us is the engine and transmission. Night and day from what I've read.

 

I have an 08 Rubicon and went from 33's to 35's running 4.10's. I was sure I wanted 4.88's but after doing a ton of research and talking to the shop,I decided to go 5.13's and I am glad I did. I think if you go with 4.88's you will be disappointed especially if you are going to 35's. Just my opinion.

 

Get 5.13's and call it a day. I run 35s with a 3.8 auto and it drives great but at times I wish I went with 5.38's.