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-   -   4.56 and 31" tires (http://www.wranglerforum.com/f282/4-56-and-31-tires-149833.html)

jim9006 03-29-2012 12:31 PM

4.56 and 31" tires
 
Just picked up a set of axles (d30/rubi d44) with 4.56 gear sets. Problem is a 31" tire is as big as i'm going - I'd like to know who's run this combo and what was it like on the freeway, gas milage, etc.... And NO I'm not going 33"'s ever! (for now)... Oh, and I have an '06 tj with the automatic OD and 4.0l

oIIIIIIo 03-29-2012 02:14 PM

The 4.56 gears with 31" tires are way too low of a gear for the size tires. Your RPM will be too high and will not save you any gas.

Wanna sell the axle to me?:)

jim9006 03-29-2012 03:18 PM

No offence but Iím looking for those who have run that combo.. I believe you that the gas mileage will most likely suck but Iím not so sure the RPM will be out of whack as bad as most think. I have the latest 4sp auto with OD. This just might work out. Oh, and yes I have a Dana 35 that Iíd be more than happy to sell you. :thumb:

TJspeed 03-29-2012 03:25 PM

i got a D30 and D44 with 3.73 thats what you need. wanna trade?! lol

jim9006 03-29-2012 03:34 PM

For the D35? ... Yeah!

TJspeed 03-29-2012 03:50 PM

no no no lol you give me the rubi 44 and i give you my 44. lol

jim9006 03-29-2012 03:58 PM

There is another thing about the rubi d44 that was as much a motivator as anything. And thats disk brakes! So there will be no gett'n rid of my new rubi d44.

TJspeed 03-29-2012 04:11 PM

and air locker

BLK00TJ 03-29-2012 04:12 PM

Quote:

Originally Posted by TJspeed (Post 2197113)
i got a D30 and D44 with 3.73 thats what you need. wanna trade?! lol

Dang it! You beat me to it. Probably closer anyhow:banghead:

Sccafire 03-29-2012 04:38 PM

Use this link. It will tell you the numbers you are looking for.

Gear Ratio Calculator

jim9006 03-29-2012 04:50 PM

Quote:

Originally Posted by Sccafire (Post 2197313)
Use this link. It will tell you the numbers you are looking for.

Gear Ratio Calculator

Thank you sir, that was a huge help! Looks like about 2400 rpm at 70 when using my OD. Whoo Hooo, that will work for me especialy since no re-gearing required.

oIIIIIIo 03-29-2012 05:09 PM

Quote:

Originally Posted by jim9006 (Post 2197357)
Thank you sir, that was a huge help! Looks like about 2400 rpm at 70 when using my OD. Whoo Hooo, that will work for me especialy since no re-gearing required.

Nice, I am at 2900-3000 rpm at 70mph. Mine is 3spd auto with 4.10 gears.

oIIIIIIo 03-29-2012 05:11 PM

Quote:

Originally Posted by jim9006 (Post 2197093)
No offence but I’m looking for those who have run that combo.. I believe you that the gas mileage will most likely suck but I’m not so sure the RPM will be out of whack as bad as most think. I have the latest 4sp auto with OD. This just might work out. Oh, and yes I have a Dana 35 that I’d be more than happy to sell you. :thumb:


No offense taken...

I have a rubi 44 in the rear also:thumb:

TJspeed 03-29-2012 07:50 PM

Quote:

Originally Posted by oIIIIIIo (Post 2197427)
Nice, I am at 2900-3000 rpm at 70mph. Mine is 3spd auto with 4.10 gears.

ouch.. my 5 speed with stock 3.73 with 33''s doing 83MPH (speedo says 75MPH) im at 3000RPM in 4th gear 5th is like 2500 or something.

netlohcs 03-29-2012 09:38 PM

I ran nearly the same setup (I had 30s) for a while, but I had a manual transmission, so I'm not sure that my experience would apply to you.

doclouie 03-29-2012 10:10 PM

I want to say at 75 MPH I am at 3750 RPM with 4.10 gears and 31" tires. That is with the 3 speed tranny.

GoldenSahara00 03-29-2012 10:13 PM

That's way too deep IMO. Why get the axles is what I'm wondering. Want to trade?

NickDanger 03-30-2012 12:42 AM

Um, how did I miss a Rubi D44 and D30 with 4.56s on craigslist (assuming you picked it up from craigslist)

If you decide to get rid of them for any reason, let me know, I'm actually in WA unlike these other guys haha

somis 03-30-2012 01:54 AM

Ive got a 5 speed manual with 31's and the 4.56's but a D35 in the rear. It is terrible on the freeway but does great on the trail

netlohcs 03-30-2012 02:02 AM

anyways, to add my opinion - if "freeway" is involved at all, don't do it. It would (in my opinion) be great for blasting around town though. Are you getting sick of the "wanna trade, tee hee" posts yet?

BroderickMi 03-30-2012 04:15 AM

I’m not so sure the RPM will be out of whack as bad as most think.
http://www.australialuxe.info/013-1.jpg

onejsmith 03-30-2012 12:08 PM

4.56 and 31s
 
Quote:

Originally Posted by jim9006 (Post 2196634)
Just picked up a set of axles (d30/rubi d44) with 4.56 gear sets. Problem is a 31" tire is as big as i'm going - I'd like to know who's run this combo and what was it like on the freeway, gas milage, etc.... And NO I'm not going 33"'s ever! (for now)... Oh, and I have an '06 tj with the automatic OD and 4.0l

I will admit that I have no direct experience with the ratio/tire size you are asking about... but this might give you something to think about.

The TJ Rubicons came stock with a set of 31s and ran the 4:10/1 ratio. Some of the others have mentioned your RPM will be high on the road with the 4:56 ratio. They are absolutely correct. Your mileage will suffer some too. You will be out of the "sweet spot" for HP and torque both on and off road. Off road you may not care as the slower crawling ratio will be to your advantage.
If you care at all about the mileage, change the gears to the 4:10s.
Happy Trails.

jim9006 03-30-2012 03:14 PM

1 Attachment(s)
Hello All,
So what I see here is that no one has tried the 4.56 and the 42RLE automatic. I know 4.56ís and 31Ē tires would never work on a normal (insert reality land here) jeep. But the 42RLE has a 0.69 OD for a 4th. I believe the earlier auto trannies were 1.0 in top gear. Thatís why Iíd like to hear from someone whoís been there / done that. Donít get me wrong guys, I love ya all and such but youíre filling my thread with crap. Oh and for those who keep asking me to trade/sell/whatever. Please stop. Iím perfectly capable of regearing my own axles as I have done it many times, so if it comes to that Iíll regear them before I sell them. Iíve asked these questions because the 4.56ís are already in there and ready to go and if this OD thing works as the charts say it should (somewhere between 2400 and 2700 RPM at 70mph) Iíd have a totally sweet setup for both off and on road and still have the option of not regearing when/if I ever go bigger on the wheels.

InvertChaos 03-30-2012 03:48 PM

I would imagine it wouldn't be too terrible seeing as 4.88 is recommended for 33s on that transmission, it would make sense that 4.56 would be alright for 31" tires. No one has any personal experience because most people on 31" tires aren't looking to swap axles or have plans to go larger. You seem to have plenty of mechanical experience if you can regear a diff, so either play with some rpm calculators or swap them on and take a test drive.

jim9006 03-30-2012 05:10 PM

Invert,
Can you supply me with the source of your information on the gear recommendations for the 42rle? I think your right. I'm going to have to install the rear axle and try it out.... Now I just need to get some 31" wheels.
FYI: I will report back with my findings for future archives.

InvertChaos 03-30-2012 05:38 PM

Quote:

Originally Posted by jim9006
Invert,
Can you supply me with the source of your information on the gear recommendations for the 42rle? I think your right. I'm going to have to install the rear axle and try it out.... Now I just need to get some 31" wheels.
FYI: I will report back with my findings for future archives.

Sure, ill try to dig one up. I just kind of have them memorized from Jerry B's recommendations. For the I-6, 33s, and 3 speed its 4.11, 5 speed is 4.56 (what I have), 4 speed is 4.88. If someone has a 4cyl its just a step up for each one, and another step up for each increase in tire size.

GoldenSahara00 03-31-2012 12:06 AM

Quote:

Originally Posted by InvertChaos

Sure, ill try to dig one up. I just kind of have them memorized from Jerry B's recommendations. For the I-6, 33s, and 3 speed its 4.11, 5 speed is 4.56 (what I have), 4 speed is 4.88. If someone has a 4cyl its just a step up for each one, and another step up for each increase in tire size.

What does this teach us? The 32rh was the best transmission ever! :rofl: as far as stock tjs.

jim9006 05-02-2012 12:01 AM

UPDATE: Axles installed. 42RLE / NP231 4.56 w/32" JK wheels, SS SYE (tom woods) and the rig drives perfect. I've only driven it to work so far. Got it up to 50mph with no vibes and rpm at aprox. 1900. Looks like the 4sp OD by pass button is no logger required. I'm like'n it.


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