ronjenx

If I understand your question correctly, you are asking if you will get a lower ratio by going to 5.13 gears, or going to a 4:1 t-case.

Don't you already have a Rubicon with 4:1 T-Case?

Here are the ratios you are dealing with:

2.73 X 4.10 = 11.2 --------(Non-Rubi with 4.10 axle)

2.73 X 5.13 = 14 ----------(Non-Rubi with 5.13 axle)

4 X 4.10 = 16.4 ------------(Rubi with 4.10 axle) (This is yours?)

4 X 5.13 = 20.5 ------------(Rubi with 5.13 axle)

toymaster

If you are happy with your highway performance and are only conserned about crawl speed then you need an atlas transfer case. You can get some insanely low ratios. The only time the gearing will change is in low range.

Changing your R&Ps will lower the ratio all the time and is the best mod hands down after the lift/tires. Many, many threads about that one.

If you run 75 a lot I'd say put in 4.88 and the atlas transfer case would be the best of everything (except for your wallet). I love my 5.13s but I stick to 60 - 65mph so I can average 18mpg.

4.88s will put you back to factory.... 5.13s put a large smile on my face while factory tires and 4.1 did not....that being said at 75mph & 5.13s the RPMs will be to high for good MPG figures, someone else may comment on the fuel mileage at that speed.

VaNomad0530

x2 what everyone else has said about doing the transfer case. I have 4.88's with 35's and a manual tranny. I think it works great on rocks btw and I don't have the Rubicon Tranny...which I'm sure would make it even better. I think if you went 5.13's and wanted to hit 75 on the highway you'd really be pushing your motor. I honestly don't like going over 70 too much unless I have to pass someone and it's only for a short while. The RPM's are are pretty high just with 4.88's.

It would be good to hear from someone who has 5.13's who drive on the highway though. Hope this helps...of course you could always do both if you really wanted too

JPop

Solving a final driveline ratio for off road use with rear end gears would be a bad idea. Most people have wants of both better on road and off road performance, but as stated this doesn't seem to be at issue. In the end you can either incrementally upgrade your final driveline ratio for off road use while dramatically improving your on road performance by way of rear end gears or dramatically improve things off road via a replacement transfer case while doing nothing for on road performance.

My advice would be to step back for a moment and figure out what you really want to accomplish.

rhino4bs@yahoo.com

will 513s make it quicker on road or slower from say 0-60

VaNomad0530

It will be quicker off the line but that's it. 1st gear will be useless for you. I don't know what your top speed would comfortably be to you though. It'll definitely be less....if you're looking to go 75-80 I'd say forget it. Then again that's something I'd ask around to people who have that particular setup with 5.13's and 6 speed manual seeing how I have the 4.88's and 6 speed..

VaNomad0530

I'd have to agree. If you're only going wheeling a couple times a month it wouldn't be worth it to me. To each his own though. Mine's a daily driver and I try to go out as much as I can, but I still need it to drive decently for me on the road.

Good luck with your decision!

captjay

atleast i wasnt the only one who wasnt sure what he was asking. kinda sounds like 2 qusetions into one.

btw, if i may interject on this, the ratios will actually be numerically higher than what you have. also figured in is gear ratios of the tranny and tire size

JPop

It'll make you quicker for the first 60 feet and that is where most people will judge their improvements. Not going to be any difference after that, outside of perhaps needing an additional shift to get to 60.

ronjenx

I didn't include transmission gears or tire size because he defined them in his original post, making them constants. That's why I included only the variables. He was looking for the combination that would yield the lowest gear ratio.