kh202

I'm getting around 14-15.5 mostly highway now, only using 5th with my 3.21's I would be happy if after regear, my rpms in 6th would match my 5th gear rpms now. I'm about 2300 rpms @ 70. From what it sounds like, the 4.10s would be the ticket.

Y'all think the crawl speed between 4.10 and 4.56 is THAT noticable that i'd kick myself for 4.10's?

sgtkersh

4.56s are a better value in my opinion. You will have more power through all gears and its cheaper than paying the premium for Dana 4.10s. My fuel economy went up since the engine wasn't working as hard.

GJeep

The difference between 4.56 and 4.1 is 10% .
If the crawling speed is 3 mph for the 4.56 , it would be 3.3 mph for the 4.1 .
IMO, that's an insignificant difference for the Pentastar.

Dynomax

I think on the trail where gearing really shines is in the t-case.....
Obviously the lower gears in the diffs help you get to that final crawl ratio.

JE8154

2012 manual, 35"toyo's, had 3.21's now have 4.56. 3.21's weren't that bad on the street. I thought they were miserable on the trail. It is such an amazingly huge difference offroad. It used to go too fast to the point of it being hard to control on anything you needed to do more than just power over. Now it goes nice and slow creeping over everything without having to touch the clutch and very little gas without stalling. It's worth every penny.

70 in 6th on flat ground I think I will hold about 2700. It's a little high and my gas mileage is usually about 14.5 average but its whatever.

Edge Hawk

I think you'd be fine with 4.10s

I have heavy bumpers and winch, 4 door, auto and 35s.

Going up those hills out in western MD, where you are, for me in a 5 spd auto isnt' the greatest, but it's not the worst. So I think you being a 6spd you'd be fine.

I get avg 16.5 mpg, and I drove 840 miles round trip to VA (up to 2400' elevation) and got 16 going down and 19 coming back.

rays0852

It amazes me that people who are recommending gears to others don't know their actual RPMs at a given speed or give a 200 RPM spread.

The charts are BS for 2012s and up.

Also....if you are using a gear calculator....use the measured size of your tire mounted on the Jeep....Not the manufacturers printed size.

My 35x12.50x15 KM2s on 8" wide wheels measure exactly 33.5" on the jeep.

mistasparkl

4.56 on a '12 auto w/ 35's here. I think it drives perfectly. I'm getting 2700 rpm @ 70mph. I have added heavy bumpers, winch, armor, and sliders, and haven't lost any power that is noticeable. I want to go to 37's and wish I had gotten 4.88's only because I really like how the jeep drives on 35's and 4.56.

rickc309

I run 35's with 4:10's, I think it's a perfect match. I couldn't be happier.

GJeep

The RPM at 70mph is influenced by many things:

Head or tail wind, a small deviation from perfectly horizontal road, new or worn road, tire type, brand new or worn tires, tire pressure, fuel octane, total weight, with/without a roof rack, with/without lights on a light bar or roof rack ( + their shape & size), hard or soft top, closed or opened windows, and more variables I don't think of right now, combined together, will result in different RPM at 70mph for the same gear ratio.

Therefore, there isn't a RPM number that's true and accurate for everyone, and there may be deviations for the same Jeep.