I hear you. That's a legitimate point I was debating myself. I was hoping I could just suck it up and drive a bit slower for 6 months

 

I have a 2011 jkur with a six speed, I am running toyo m/t 35x12.5x17 tires, these tires run very close to 35" and are heavier then most. I also have added quit a bit of weight in bumpers, skid plates, winch, etc. see my sig. for details. I also live in a area with a lot of hills, very little flat ground driving. Because of all this I went with 5.13's. the difference between 4.88 and 5.13 is 90 rpm, but helps the 3.8 engine get the job done a little better. The guys at northridge 4x4 recommended the 5.13 for my setup, that is also who I had do the gear install. mph/rpm= 60mph/2400rpm 65mph/2600rpm 70mph/2800rpm 75mph/3000rpm. mpg cruising at 60-65 is about 16 mpg. mpg when running 70-75 drops to 13-14 mpg all depending on terrain. hope this info helps.

 

How long have you run it like that? Any concerns with the strength of the 5.13 gears in the D30? (assuming that is your front axle.) I have a 2010 on heavy 35's as well and was thinking I'd go 4.88, partly due to strength. Though it would also maybe make better sense for how I drive to do 4.88.

Big Truck: No Little Truck, we can't go there!
Jeep: Silly truck! I am a Jeep!
*goes there*

 

Thanks for the detailed info! I'm starting to reconsider the 4.88's based on everyone's inputs. Can anyone with 4.88's (manual tranny) provide an RPM count for 75 or 80 mph? (80 is really pushing it, I don't expect to do this except downhill on a good day passing someone).

 

That work for ya?

 

I love my 4.88s except 4hi sucks

 

But that is t-case gearing, not axle gearing? If I could find me a rubi t-case on the cheap, I'd be all over it.

Lol, just thought about that. You said 4hi

 

If I could find one I'd be all over it too...all I know is before 35s and lift everything was ok, after 35s and lift with 3.21s it lacked a lot but was tolerable driving around. 4lo and 4hi were weak. Went 4.88s and its nice to drive around, 4lo is nice and does the job, 4hi is only good for mud and snow unless there is an incline greater than like 3°

 

[QUOTE=igobytony;3968485]How long have you run it like that? Any concerns with the strength of the 5.13 gears in the D30? (assuming that is your front axle.) I have a 2010 on heavy 35's as well and was thinking I'd go 4.88, partly due to strength. Though it would also maybe make better sense for how I drive to do 4.88.

I have been running this way 6-7 months, no worries, mine is a rubicon so 44's front and rear.

 

I'm going to resurrect this old thread. I finally pulled the trigger on 4.56 gears on my 33's. What a difference. Took it out wheeling and spent most of the time in 2nd gear (lo) when before I was in 1st and wishing for something lower.

Can't wait until I move up to 35's. Should be right in my sweet spot.