Hello All,

I have a new 09' Unlimited X, automatic.. I'm installing a 4" Teraflex lift and the rubber's going to be 35's.

I've been researching here and I think my next step will be regearing.

What ratio should I do? What brand should I choose? What other options should I consider? What factors influence the answers to the aforementioned questions?

My time on the road, like most of us, is 90%. The other 10% will be off roading. I would like to be able to run it on the highway without taxing the transmission too much. My general thought process on this is that I would like to compensate for the increase tire size so that the drive train is not prematurely worn out.

Thanks

 

First, Regearing takes the load off the Tranny, and puts it on the engine to make more power... Your worry shouldnt be about taxing the tranny, but just revving to high on the engine... I would go easily 5.13... Charlotte isnt to rocky, so 5.13 should be fine...

 

I have 35s, 4" lift and 5.13 are the best choice for stock axles. I'd go a little deeper (5.38) if I had a Dana 60.

I run 80% on the fwy.

 

Thanks for the replies..

Jeeper - While driving on the hwy, what is your avg speed?

 

70-75, RPM 2400-2600 roughly. In other words, just about right.

 

Totally WRONG!

Regearing takes the stress OFF the engine and transmission and puts more stress on the axles and tires.

Simple physics. Increase ratio = increased leverage on transmission and engine side of equation so they are capable of producing more power. The axles and tires then must transfer that power to the ground.

5.13 is too high for highway use.
Keep it at 4.88 if you drive over 55 mph.
4.5x if you travel at 65 or 70 much.

 

haha... 4.56's for highway use with 35"s....hahahha... Yeah right..... At minimum go 4.88, if Auto 5.13 is way more preferable

 

5.13 Auto..............

 

From FAQ

Q: What gear ratio should I be running with 35" tires?
A: In order to bring your Jeep's performance back to stock, you will need to run 4.88 gears with 35" tires. However, if you are looking for a little extra power, you should consider getting 5.13's. This is especially desirable if you have an automatic transmission.


I have 5.13's btw, if I had a 44 up frt , woulda went 5.38's

 

Here's a chart I threw together this morning.

All speeds are at 70mph.