The rubicon came stock with 31's and 4.10 gearing. So 4.10's would be optimal but is it a nessecity? No. Its mainly up to you. After you get them on drive around with them and if you like the way it feels leave it alone if you feel you want more power then regear to 4.10's
thanks everyone.it is my daily driver and i offroad every now and then but its nothing intense, so ill see how it feels. a lot of people have been telling me i dont have to with 31's so ill see. thanks !
I am running 31's now with 3.07 gears. Not that great with all the gears that I have added. I am getting a D44 rear with 4.10 put in tomorrow and install 33's on it also. It will bring the hp back to the Jeep.
I just installed 31 X 10.5 BFG KM2's on my stock rims along with a 2.5 inch Rough Country lift and spacers up front to level it out. It rides great, there is definitely a loss of power (My stock config was 225/75R15 I6 4.0 and 3.07 gears), but nothing I would regear for.
It is still quite nimble and I'm glad I made the change. Someday if I want more I'll add a body lift, regear and 35's.
The biggest loss in power is due to the type of tire your running... If you went with a KO I dont think you would notice.. or maybe a Duratrac... When you start running big lug tires its going to take more... ATs have less rolling resistance I have 32 KM2s on my 90 YJ.. I had 35s on it.. talk about power loss