Just got my jeep back from the shop after going from 3.21 to 4.56 with 35's. only question i a ask myself is why i didn't do it sooner? its a brand new vehicle! for anyone questioning whether it is worth it or not. coming from someone as skeptical as me. Do it! i used G2 gears with install kits. my jeep went from a dog to a doll to drive.

 

On the list of wants. 3:73s currently and it's ok but I'm thinking I should upgrade. I was living with it thinking I might be getting better gas mileage, but I don't think it can get much worst thanks for the info!

 

Just what I wanted to hear. My bank account is gonna be in shambles!

 

Is this on a manual transmission? Those are the gears I am going to use when I switch to 35s on my 2012. What RPM's is it at, at 70 MPH?

 

I have a 2013 JKU Sport with the manual trans and 4.56s. On 35s I was running about 2700 RPM at 70. Now on 37" MTRs it's right about 2500 RPM. Still has plenty of power and crawls well off road. My wife has a Rubicon with 4.10s and 35s and we have similar rpms, but man does her 4:1 transfer case rock! I see an atlas in my future.


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I can't speak from personal experience, but based on the gear charts floating around those RPM's suggest you have at least 4.88 gears. Have you GPS confirmed your speedo is calibrated? 2700 rpm on 35's put you between 4.88 and 5.13. 2500 on 37's puts you at 4.88.

Curious because I am changing gearing and would like to know if the charts are wrong.

 

I have a 3.6 auto with 4.56's, speedo has been verified by GPS and I'm seeing 2700 at 70mph. The difference for me is my "35's" actually measure 34".

 

Ditto on verification. Weight is going to be a factor as well. My JKU weighs over 5100 lbs on a truck scale.

 

My 35s also measure 34" or so and my 37s measure just under 36" right now.

 

Just the info I've been waiting for. Currently running my 13 JKU auto with 3.21's and 35's and it sure needs to change.
4.56's it is. Thanks for the great info.