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Author Topic: more Re-gearing discussion please  (Read 3223 times)

Offline BigMike

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Re: more Re-gearing discussion please
« Reply #12 on: August 24, 2017, 12:45:09 PM »
dont get over sold on the D44 plenty of guys run D30 with 35's and have never had an issue, unless ur hard on the skinny pedal u should be fine for a long while.   just my .02 and experience.    i actually ran it, wheeled it, no breakage.   the 5.13 gears are tiny for a D30 but 4.88 would be just fine IMO.

I might not agree often with Kent, but this time I do.

I do agree with Kent to a point.  You can't plan to any degree of accuracy of the situations you can get into.  There could always be that time when you get into something that requires full torque to get you out.  Remember, the D30 only has a 7-1/8" (vs. D44 8.5") ring gear and when you gear it to 5.13 or lower, you're putting more torque and stress on it then it was ever meant to take.  Add to that the extra 20+ lbs of wheel and tire with less backspace (spacer or wheel) and it won't take a lot to break.  It comes down to always running on the edge of danger or running in the sweet spot.

Your rig, your choice.  It's like the guy on GATR Facebook page that is running 40's with "built" 44's and says he wheels it.  Just because you can, doesn't mean you should. 
« Last Edit: August 24, 2017, 12:50:37 PM by BigMike »

Offline flimflamman

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Re: more Re-gearing discussion please
« Reply #13 on: August 24, 2017, 12:59:54 PM »
Planning  to regear and add lockers, (Hopefully before Christmas)....for my 3.6 Auto, d30, and staying with 35's will 4.88 or 5.13 serve me better?

I basically have the same setup as you, except I have a 6 speed. After adding a lift and 35's, I was thinking 4.56 would be plenty for a daily driver/off-road weekend warrior. Should be a dramatic difference coming from 3.21.

Seems to me with 5.13's you'd be revving high cruising 70 (not that the powertrain couldn't handle it though). I take a lot of road trips so that would be a factor for me.
Mike Y
2016 JK

What we've got here is failure to communicate...

Offline DOUG

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Re: more Re-gearing discussion please
« Reply #14 on: August 24, 2017, 01:41:01 PM »
I don't know what the 3.6 auto or 6 speed is turning with 35s or 37s at 75 or 80 mph

but trust me.  You'll hardly notice. 


Assume      4:88 is      2000 rpm
Then          5.13 is      2102 rpm   +102
Then          5.38 is      2205 rpm   +205    barely noticeable difference 10%

Assume      4:88 is      2500 rpm
Then          5.13 is      2628 rpm   +128
Then          5.38 is      2756 rpm   +256    barely noticeable difference 10%

Offline DOUG

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Re: more Re-gearing discussion please
« Reply #15 on: August 24, 2017, 02:05:53 PM »
I basically have the same setup as you, except I have a 6 speed. After adding a lift and 35's, I was thinking 4.56 would be plenty for a daily driver/off-road weekend warrior. Should be a dramatic difference coming from 3.21.

Seems to me with 5.13's you'd be revving high cruising 70 (not that the powertrain couldn't handle it though). I take a lot of road trips so that would be a factor for me.

Your difference is HUGE from 3.21:1 but tire size eats it up fast. 

Offline Jango

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Re: more Re-gearing discussion please
« Reply #16 on: August 24, 2017, 02:31:09 PM »
I don't know what the 3.6 auto or 6 speed is turning with 35s or 37s at 75 or 80 mph

but trust me.  You'll hardly notice. 


Assume      4:88 is      2000 rpm
Then          5.13 is      2102 rpm   +102
Then          5.38 is      2205 rpm   +205    barely noticeable difference 10%

Assume      4:88 is      2500 rpm
Then          5.13 is      2628 rpm   +128
Then          5.38 is      2756 rpm   +256    barely noticeable difference 10%

On my 3.6 Auto. Running 4:56 at 70-75mph sitting on 3k rpms on 35" tires.
« Last Edit: August 24, 2017, 03:52:12 PM by Jango »
-Connor (Jango... the D is silent and invisible)

Offline flashover101

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Re: more Re-gearing discussion please
« Reply #17 on: August 24, 2017, 03:10:16 PM »
I run 4.88 on D30 and locked and use it sparingly as a DD. Perfect gear choice in my opinion. I'm methodical when wheeling and don't anticipate a problem 🤞
Mike
2014 JK

Offline kvom

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Re: more Re-gearing discussion please
« Reply #18 on: August 24, 2017, 03:15:08 PM »
As always, wheeling style/skill counts for a lot.  Most axle breakage is a result of bouncing while powering or wedging the tires.
00 TJ  stuff
02 F250 CC LB 7.3 tow pig
18 Honda CRV
12 Chrysler 200 - Wife's car

Offline flimflamman

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Re: more Re-gearing discussion please
« Reply #19 on: August 24, 2017, 03:17:56 PM »
I don't know what the 3.6 auto or 6 speed is turning with 35s or 37s at 75 or 80 mph

but trust me.  You'll hardly notice. 


Assume      4:88 is      2000 rpm
Then          5.13 is      2102 rpm   +102
Then          5.38 is      2205 rpm   +205    barely noticeable difference 10%

Assume      4:88 is      2500 rpm
Then          5.13 is      2628 rpm   +128
Then          5.38 is      2756 rpm   +256    barely noticeable difference 10%

Ok cool... much less than I thought.

IIRC (and I'll check on the way home tonight), 3.21 on 32's in 5th gear (6th sucks at this point) is 2900 at 80 mph.
Mike Y
2016 JK

What we've got here is failure to communicate...

Offline DOUG

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Re: more Re-gearing discussion please
« Reply #20 on: August 24, 2017, 03:20:59 PM »
I don't know what the 3.6 auto or 6 speed is turning with 35s or 37s at 75 or 80 mph

but trust me.  You'll hardly notice. 


Assume      4:88 is      2000 rpm
Then          5.13 is      2102 rpm   +102
Then          5.38 is      2205 rpm   +205    barely noticeable difference 10%

Assume      4:88 is      2500 rpm
Then          5.13 is      2628 rpm   +128
Then          5.38 is      2756 rpm   +256    barely noticeable difference 10%

On my 3.6 Auto. Running 4:56 at 70-75mph sitting on 3k rpms.

Tire Size?

Use that engineering hocus pocus to figure 35's and 37s with PI

Offline DOUG

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Re: more Re-gearing discussion please
« Reply #21 on: August 24, 2017, 03:22:38 PM »
I should say I NEVER recommend 5.38 for a Dana 30.  Probably never more than 4.88 :1 becuase the gears are SO TINY. 

Offline Krawler00

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Re: more Re-gearing discussion please
« Reply #22 on: August 24, 2017, 04:18:21 PM »
So if you plan on running a larger tire in the future, save your money and find a 44 somewhere. I know alot of guys who run the D30 without any issues. Todd runs one in his CJ and he beats that thing on 35's. I ran a 30 years ago before I swapped to the waggy front and never had an issue with it and the aussie locker. But I only ran 33's on it for fear of going to big on it. So if you are a mild non heavy footed driver keep the 30, plan on going bigger tire etc, save for a 44. But there has to be better deals out there or somebody selling a stock 44 housing cheaper than $5-6000!! Build one.
I've grown tired of this.

Offline Big Dave

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Re: more Re-gearing discussion please
« Reply #23 on: August 24, 2017, 05:07:41 PM »
In a Dana 30, with 5.13s, there is only one tooth on the pinion in constant contact with the ring gear. I think 1.5 or 2 with 4.88s.
Most Dana 30 owners don't go above 4.56 for this reason. Insurance.
Personally, I'd get a Rubi 44 & sail the 30.

 



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