Make My Gearing Decision (ugh)

4.10 or 4.56

  • 4.10

    Votes: 10 30.3%

  • 4.56

    Votes: 23 69.7%
  • Total voters
    33
N

notamos

NAXJA Forum User
Location
Fort Collins, CO
I know, I know... I HATE it when the subject of gearing comes up on Jeep forums. Especially the old 4.10 vs. 4.56 threads. I thought I'd post it in here as altitude is an aspect of this debate in my mind.!!!1

Here's my deal. I'm lifted about 3.5" right now and am running a brand new set of 31x10.5r15 BFG ATs. I am having Dutch regear my rig next weekend but can't settle on 4.10s or 4.56s. I have the 4.10s in my garage right now but can swap them out with 4.56s easily. Specs are HPD30, 8.25, 231, 99 XJ, Newly-built engine (750 miles on it), AW4.

My XJ is my daily driver (around Fort Collins) and is my hunting/camping rig. It is driven mostly around town but will require some 4-6 hour drives for hunting. It is not for the rocks, mainly logging roads & some moderate trails just to get back in to hunt. I'll have it loaded up with hunting gear for those drives. It will have some armor (gas tank skid, after-market bumpers, rails) and a winch.

As of now, I don't have plans to run anything larger than 31s as they are brand new (750 miles on them!) but I can see myself going to 33x10.5s in a couple of years once these wear out.

So, 4.10 or 4.56?
 
Yes 4.88s are the lowest for both of your axles to my knowledge. For what's its worth my jeep was reheated to 410s when I was on 31s then I went to 33x10..5s and then 35s where I reheated to 4.88s an now with the 37s it is better than the 35s IMO. But I have an ax-15. With the aw4 or other autos like my dads, he is running 4.88s in his lj with 32s and it is only ok.
 
Frank Z said:
Use the gear calculator at www.grimmjeeper.com
[/thread]
Click to expand...

I've used it, all day!

4.10, 60mph, 31s = 2019
4.10, 70mph, 31s = 2356
4.10, 60mph, 33s = 1896
4.10, 70mph, 33s = 2212

4.56, 60mph, 31s = 2246
4.56, 70mph, 31s = 2620
4.56, 60mph, 33s = 2108
4.56, 70mph, 33s = 2460

Stock:
3.55, 60mph, 28.3" = 1898
3.55, 70mph, 28.3" = 2214

If I go w/ 4.56s and run them w/ my 31s for few years - I'll be about 400rpms higher than stock. W/ the extra weight from armor, bumpers, winch, gear - this doesn't seem like much. The 4.0 @ 2600rpms seems ok to me. End of thread?
 
With an AW4 and 32's I was running close to 2800rpm at 70mph and thought it was way over geared. With the 35's I feel under geared but not terribly so. If you aren't ging any bigger than 31's then just stick with your 4.10's you've already got. If you decide you want more gearing later, well I'll probably be selling my axles come summer time.
 
I have a very similar setup to you and the 4.10s are great with the 31 ats. In my opinion pickup is slightly better than it was with 3.55s and stock tires. I drive in the hills a lot to go skiing and camping and it is the right set up in my opinion. But...I do plan on going with 33s for my next tire and will definitely want to regear to 4.56 at that point.
 
UnlimitedMatt said:
I'd go as high as you can. Do it right the first time. Not many people complain about having too low of a gear.
Click to expand...


When you're engine is screaming at 3000rpm while doing 75mph it can get a bit annoying. Hurts fuel economy too.
 
Decision made. I swapped the 4.10s for 4.56s. How I made the decision - I put it in third, headed out on the highway and drove it at 2250rpms for a while and then at 2700rpms - where it will be with 30.7" tires and 4.56 gears, in overdrive (.75 of the aw4). It felt nice & smooth, definitely in the power band. This thing is going to climb passes like a goat.

So, Dutch will set it up & I'll end up going to 33s sooner rather than later! ;-)
 
DutchVDub said:
When you're engine is screaming at 3000rpm while doing 75mph it can get a bit annoying. Hurts fuel economy too.
Click to expand...
When you drive a jeep you are going to be down shifting and sitting in that 3000RPM range anyways so you can keep your speed going up the mountains!
 
I believe Dutch is talking about when you're driving straight down I-25 @ 75mph - having your engine screaming along @ 3000rpms could get annoying. I agree w/ this. But, I usually don't drive real fast and I'm hoping to get 33s sooner rather than later.
 
Meh turn the music up. With 4.88s and small 35s (measured about 32~33") I could buzz 85 at 3500RPM.. I made much of my commute from Westminster to Lakewood just like that
 
Yes, and when you get older you'll realise that you like peace and queit sometimes.

That said, if I didn't have that stupid THOR intake I wouldn't mind the rpm's being up there as much. I'm definitely going to be ditching that annoying arse thing soon.

So am I now doing 2 axles on your rig?
 
never...
4618164610_25159bf48f_z.jpg
 
Whatever man, thats why I drive the Audi. Its nice, comfy, and quiet. Even while doing 140kph down the interstate. :D
 
Last edited:
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