TheDragonTJH

There are hundreds of threads full of opinions on what gearing is "teh best!1!", there are dozens of variables from tire size to terrain to highway/offroad and I don't believe there's an absolute answer, so for a Jeeper who hasn't done this before it's certainly overwhelming. So, I thought it might make sense to discuss this in a more informational sense. Let's hear the first-hand experience with your rig.
*Gear ratio?
*Engine and tras. type?
*Tire Size?
*Daily Driver vs. Dedicated wheeler or some mixture of the two?
*Describe your on-road driving experience, normal terrain, highway speed RMPs, uphill power, etc.
*Describe your off-road experience
EDIT: Please add any other information you think would be important a person considering a regear should know.

TheDragonTJH

*Gear ratio? 3.21
*Engine and tras. type? 3.6, Automatic
*Tire Size? 315/78R17, Cooper MTPs
*Daily Driver vs. Dedicated wheeler or some mixture of the two? Mostly a daily driver with a trip to wheel about once a month. It is also the family wagon, we road trip quite a bit with it.
*Describe your on-road driving experience, normal terrain, highway speed RMPs, uphill power, etc. No surprises here, it struggles to keep highway speed uphill, it's a bit sluggish from a full stop.
*Describe your off-road experience It does pretty well, but then again I don't know better.

I am all set to regear, so I will be watching this thread closely to help me decide on the gear ratio that makes the most sense for my rig.

resharp001

Well, one thing to keep in mind is there are not limitless selections of gearsets for our JKs. Usually, you’re gonna be hemming and hawing between two choices….with one of those bordering on the aggressive side. I’ll throw my experience out there and you can take it with a grain of salt.

Rig – ’13 modified sport S (non-rubi TC)
Engine/tranny – 3.6L auto
Gear set – 5.13 (yukon’s in D44 rubi axles)
Tires – 37” Nitto Trail Grapplers on 17” wheels inflated to 28psi cold on a light’ish jeep (Stubby stinger up front, skinny rear bumper with no spare, but do have armor around and skids underneath)

General use – no longer a daily driver. It’s a part time driver/toy. Bought a $2800 pos commuter car to save wear and tear on my baby. Live in Texas so generally flat land, but it travels to Colorado and other elevations. I live outside of town so most my driving is highway type stuff….which is 70mph or more. On long road trips I’ll push 75mph or more…..whatever the speed limit is (it’s 80 out in west TX!). I wheel it pretty decent….it’s not a pavement queen.

On-Road experience – it’s geared lower than most would like. Aggressive on the pavement. It’s nice to hold gear in to a stiff headwind on the highway or going uphill. Can’t complain about the power/pep (don't expect more power like you just did an LS swap or added a RIPP, but it feels like it "should"). Major downside is running 3k RPM around 70-72 mph. Most people wouldn’t like that, and it sucks the gas down fast. I typically get ~14mpg around home per the computer…..usually 13.5 if calculated manually (yes, everything is calibrated). Wanna question what that’s like on the top end…..force your jeep into a lower gear till you’re running 3k rpm at highway speeds for an extended period of time. One quirk that gets to me after regearing….accelerating hard to get on highway it will stick in 3rd gear for a LONG time….like up to or over 5k rpm before shifting. IMO, MOST people with my set up would want 4.88.

Off-Road experience – mine plays in the rocks mostly. I have no complaints about the gearing off road….especially since I don’t have rubi TC. I can tell a big difference coming from 4.10s previously. I would probably have been just as happy with 4.88s tbh.

If I had it to do all over again, I would probably go with 4.88’s just to keep it a little more well rounded in case it had to become a daily driver again. I have no complaints for its current use, but the high revving on the highway takes its toll on the fuel gauge.

You mention yours does “pretty well” off road as it is. If your wheeling is on the lighter side….fire road type of stuff, you’re not going to notice much difference off-road. If you are in to rock crawlin’ type stuff, what you’d notice is being able to move through things at a slower, more controlled pace. It would be a considerable difference with your non-rubi TC.

rob_engineer

Stock 2012 jku Sport. Manual trans. 3.73 gear ratio. I've towed a 5000 pound trailer all around the east coast. Stock tire size. Now I have a 2000 pound cargo trailer. I wish I had the 4.1 gearing. At highway speed of 65mph, the rpm band of the 4.1 has about 10% more horsepower compared to the 3.73. The 3.73 gets the job done, but the 4.1 would help me maintain speed on highway during inclines.

NevadaZielmeister

*Gear ratio?
-5.38
*Engine and tras. type?
-3.6 L Automatic
*Tire Size?
-37 inch Nitto Trail Grapplers
*Daily Driver vs. Dedicated wheeler or some mixture of the two?
-Mixture of the two in that I only drive to work about once per week.
*Describe your on-road driving experience, normal terrain, highway speed RMPs, uphill power, etc.
-Off the line it is really great. I can accelerate pretty good around town. Not a sluggish response at all. Going uphill is only challenging due to the increased weight of my JK with all of the axle, suspension and armor upgrades. But I can get up some hills pretty good.
*Describe your off-road experience
-Really this is the element it was meant for. I love the super low crawl ratio of 77:1. I am pretty much crawling at 1.8 MPH while at 2,000 RPM, which is pretty cool. I also like when I am crawling down large obstacles, the control is perfect.

I would not recommend going to 5.38 unless you change your axles. I have a ProRock44 front and a ProRock XD60 rear. After 17k miles I have had no problems and have been over some pretty tough obstacles, fully locked and so far, no breaks. I have yet to hear or see any pictures of a ProRock 44 ring and pinion break or a housing crack. People tend to disagree with my 5.38 gear choice, but so far I really like it.

resharp001

What kinda RPMs do you see at highway speeds with those 5.38s and 37s. I can't imagine pushing higher than I already do with my 5.13s and 37s.......and it seems like we generally use our jeeps similarly in regards to occasional driving and offroad toy. I know it's dumb, but what kinda fuel economy do you see? generally 12-13? I'd think a smidge less than me as you have extra weight.

NevadaZielmeister

I see right around 3,000 RPM's on 37's at 70 MPH. Your 5.13 gears are good as well. The fuel economy is around 14-15 MPG. I'll see 13 MPG around town and then 14.5 highway average, but if I do a long trip, I have seen 15 MPG.