I recently bought me a 2011 JK with 4" lift on 35x12.50x17 inch Nitto trail grapplers. I'm planning on having my JK re geared and I'm not sure if I should run 513 or 538 gears. It has an auto tranny as well. Mostly highway driving and very little towing. Any advice will be greatly appreciated.

 

5:13 would be my pick unless you plan on going much larger in tire size.

 

No I think I will stick with 35" tires. What kinda RPM you think I'd be turning at 75mph? And thanks!

 

You have a front d30? Can you even find 5.38's anymore?

I am running a 4door auto with short 35's. Started with 5.13's, and swapped to 5.38's when I upgraded to a front 44. Many people like 4.88 and 5.13 for the 3.8 autos, but 5.38 is the better ratio for me.

For the rpm's - stickied to the top of this modified area are some faq's. In those faq's is a drivetrain section. In that drivetrain section are some charts built specifically for the JK. Be sure to use actual measured tire height, not mfg's spec.

 

Yea after reviewing the cross reference chart I definitely think 538 is the way I'm going to go. That's for the feed back and advice! Will update with results of my gearing and progress!

 

With 35" tires and mostly highway driving I wouldn't go with 5.38 gears. I have 37" tires and 5.38 gears and it is great in the city. On highway I feel my rpms at 75-80 are a tad high.

I know you've made up your mind. I just thought I would put in a vote for the 5.13 gears with 35s.

Definatly let us know your decision and how you like it.

Sorry if I make you second guess your decision. Just thought I would help you with your purchase by giving you my 2 cents.

 

I would also recommend 5.13's. I run 36's, mind you I have a 6 speed, but I'm at 3000rpm at 74mph in 6th gear and 3200rpm at 80mph and my gas mileage sucks at that speed. If you were going to 37's I'd say 5.38's.

 

Roscoj & Donny... Thanks for your advice and this exactly the type of feed back I need an am looking for. So say I would pull a small trailer with 3 dirt bikes would the 5.13 still be a good choice? I know anything is better then what I have. Thanks again

 

I went with 5.13 with 37's and think it's perfect. I drove a few days on 35's with the 5.13 and personally thought they were a little too low for me. But I would go with 5.13 if you ever had a thought of going bigger (it'll happen, it always does) or if you plan on towing something.

 

JKUrubi... When running the 35s w/ 5.13 did it hold good on the interstate or did it wanna kick out of overdrive a lot? We have a good bit of rolling hills where I live and just wanna keep it from always juking out in in over drive. Thank you for your feed back and advice also!