Baddkarmaracing

I have narrowed my gear/diff choices down to: 4.88's or 5.13's and Detroit tru tracs or regular Detroit lockers front and rear. I just don't know which combo to go with.

my story: I do not do much wheeling as is but would really like to start, I have a small group of friends that wheels, its been awhile since any of them have really been out but they are working on getting out again, so we are looking at making some trips soon and I want to be able to go, even though I know I cant keep up but I want to try lol. I am trying to get a few things out of the way so when we do go wheel I am not completely disappointed in the performance. I fully understand that I cant keep up with these guys on 40's and d60's with real long travel suspension but I want to do as good as I can and I also fully understand that I very well may break my jeep trying to keep up but that's the fun part lol

my jeep as it sits now is on 33's with factory 3.73's at stock height but I have a RK 2.5" max travel kit that is just waiting on shocks. I am trying to sell the 33's and buy 35's, which I wish I had done to begin with but oh well, live and learn right?

Rancho

my vote is 5.13.
I am on 38's and 5.38's real peppy. 2013 JKU.

Baddkarmaracing

but will it be too much gear for the 33's in the case it takes a while before I go 35's? I need to be able to drive 70-75 like I can right now, I just want to get rid of the going in and out of overdrive on the road

Rob 12B1P

Should be ok with 5.13's according to the gear chart.

nthinuf

You have a 3.8 auto, correct?

You will be fine with 5.13's and 33's. I ran 33's (32" measured height) for several months before finally getting the 35's.

But, start plugging numbers into the chart above and see what you come up with. Use actual measured tire height, not mfg spec. And if you want OD/Off rpms, just divide the result by .69 (this simulates you reaching down and pressing od/off, and can be useful for getting an idea of where bigger tires will put you)

Ex. 3.8 auto:
3.73, 32" (actual height) = 1892 @ 70 (close to where you are now? Depending on the height of your 33's)
5.13, 32" = 2603
5.13, 34" = 2450

And with OD/Off:
3.73, 32" = 1892 1892/.69 = 2742

So pushing OD Off right now with your 33's would put you about 139 rpms higher than 5.13's (with OD On). That should be close enough to give you an idea of what it will feel like. And my opinion, 2600 rpm isn't a bad place to be for a 3.8 auto, easily doable until you get the 35's. (I ran 5.13's with 33's and 35's. Then 5.38's with 35's and now 37's. I tend to like the slightly higher rpm's)

But, you also have to take your location and normal driving into account to decide what ratio is right for you.