sup guys
I am running 32" tyres at the moment on my rubi and im going to be getting some 35" muddies. she is already a slug taking off and iv been told to change the diff ratio. im a bit of a newby with this stuff and not exactly sure whats involved with this process, any help would be appreciated.
thanks

 

With your 2007 Rubi Unlimited and six speed, you'd see a good improvement if you went to 4.88 gears. Basically, you'd get roughly 20% more torque at the wheels due to the gear change. On top of that, you'd be running higher up on the torque curve where engine output is higher, so you'd also see an improvement in such things as 65 MPH to 75 MPH acceleration (for passing). The down side is at each speed you'll be running higher RPMs. This is most notable at highway speeds in sixth gear where you don't have another gear to shift up. You should find the following chart informative ...



What's involved is some pretty intricate work installing the new gear set. The actual business of making the swap is pretty straight forward. However, setting up the gears is critical. That consists of using Prussian blue to check how the gears are meshing, then shimming the gears to get an ideal mesh. If done improperly, you can destroy your new gears. It is not a recommended task for the inexperienced. Suggest you discuss your needs with a favorite 4X4 shop.

 

https://www.jk-forum.com/forums/jk-w...gearing-82262/

 

Another thing some people don't think about is the amount of weight the Jeep will carry. Any extra armor, and weight of tires can drastically affect performance. Went from 3.73's to 5.13's in an automatic 3.8 liter and still find myself hunting on windy days with 35" trail grapplers and front and rear bumpers. Just a little personal experience with gears, still one of the best investments I made in my Jeep. Also had a local shop do it after months of debating the procedure myself.