Regearing (3.21 to 4.10?) - RaccøønJK

BenJKWrangler15

BenJKWrangler15

New member
Alright lads, so I've been thinking about regearing a lot and I know all the parts I'll need in order to do it. Thing is, I'm still debating on the gear ratio I'm going to use.

Now, this is a formula I got off Can'tSayTheNameItsForbiddenByForumRules and here's how it works. You take whatever tire size you plan on running times your current gear ratio and divide the result by your OEM tire size and that should give you the approximative gear ratio you should go with in order to have the best power/fuel economy ratio out of your gearing.

So in my case, I run a 33" tire size, have 3.21 gear ratio and my OEM tire size was about 29". Sooo

(33"x3.21)/29" = 3,65 GR ish.

From there, you select the closest next available gear ratio in order to get the power/fuel economy thing going your way. So in my case I should go with 3.73, according to this equation.

Note, the number you'll end up with isn't set in stone depending on what you plan on doing with your rig and how you wheel it. It's a guideline.

Now, in order to run my 33's at the "best" possible gear ratio match, I should re-gear with 3.73.

But fxck that.

You see, it's already expensive enough to regear, now in order to do this right and only once for my own rig application and what's next to come in the future, I did the math with a 35" tire size and a 37" tire size.

Here are the results:

(35"x3.21)/29" = 3.874 GR

(37"x3.21)/29" = 4.095 GR

So running 35's, the best way to go would either be with the same GR as the 33's, 3.73, or the next available GR which would be 4.10.

If I was to run 37's on the RaccøønJK, the best GR according to the equation would be 4.10.



Now, note that my current Dana's are the 30 Front and 44 Rear as my rig is a latter 2015 JK model. To regear the front I'll need a new carrier (differential) and the appropriated gear & pinion while in the back all I'll need will be new gear & pinion.

I know the D30 is a "lemon" when it comes to bigger tire configuration and I heard my fair share on horror story related to it. But for now it'll stay as is.

I'm an NOT planning on running an air locking differential in the NEAR future for my rear D44.

With that being said, with all the math done, what would you recommend on going for as of gears & pinions?

4.10 would be ideal for both 35's and 37 inches tires. It'd be a little over rated for the 33's but from what I understand, a higher(?) ratio will end up giving you more low end torque at the wheels. When I say 4.10 would be ideal, it's by refeering to the equation results stated above for the "best" range of power and fuel economy.

But who gives a goddamn fxck about fuel economy? I ain't driving a fxcking pussy-bitch-ass-cock-blocking Prius for all I know.

Yes, it is still important to take the power/fuel ratio in mind neverthless of the fact that we see driving Jeeps. But anyways...

If I was to regear, would you go with 4.10's as the equation would suggest or a little higher for more low end torque, like a 4.56 or even 4.88?

PS : The day that I'll change my tires for anything more than a 37" will be the day I'll be putting "new" Danas under the RaccøønJK. For the time being, it'll stay a D30 in the front and a D44 in the back, unless I can put my hands on a second-hand set or front only Rubicon Dana 44s.



So, any thoughts?

Thanks in advance!

ImageUploadedByWAYALIFE1467842406.864761.jpg
 
The simple answer is no.

I don't think anyone on this forum will tell you to run 4.10s with 35s or 37s.
 
Holy fuck your thinking to much into picking a gear ratio! Look at the tire size/gear ratio chart in the noobie thread
 
If you are going to the trouble to regear, and plan to run 35s, go with a 4.88 or 5.13.
 
With 35's 4.10 would bring you back to stock performance. At least that's the way I understand it.
 
Do you plan on upgrading your front Dana 30 to a 44 at some point? If so, then just hold off on re-gearing until you get your new front axle, then do it all at once. If you have no intentions of upgrading to a 44 in the front, then 4.10 would be fine. But trust me, the more you read and hear, you're going to want to replace that Dana 30 asap...that said, i ran stock gears on my front 30 and stock rear 44 while i saved for a PR44. Built the PR44 and regeared to 4.88 all at once, and upgraded to 35 spline shafts all around. It's been a really good set up for me.
 
Agreed. If you're set on the larger tires, I would definitely swap the axle and do the gearing at the same time.
 
cozdude said:
Holy fuck your thinking to much into picking a gear ratio! Look at the tire size/gear ratio chart in the noobie thread
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Will do but I already had a chart.

Napalm said:
If you are going to the trouble to regear, and plan to run 35s, go with a 4.88 or 5.13.
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Thanks for the straight answer.

cav♤fighter;732479 said:
Nope I cant wait to shed my 4.10's. 4.88's in my future with 35's
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Good to know.

Ginz said:
With 35's 4.10 would bring you back to stock performance. At least that's the way I understand it.
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That's the idea if you only want the "stock" performance back.

Mike_JK_Houston_711 said:
Do you plan on upgrading your front Dana 30 to a 44 at some point? If so, then just hold off on re-gearing until you get your new front axle, then do it all at once. If you have no intentions of upgrading to a 44 in the front, then 4.10 would be fine. But trust me, the more you read and hear, you're going to want to replace that Dana 30 asap...that said, i ran stock gears on my front 30 and stock rear 44 while i saved for a PR44. Built the PR44 and regeared to 4.88 all at once, and upgraded to 35 spline shafts all around. It's been a really good set up for me.
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As I stated in the thread, no, not planning on going for D44 unless I find a good deal on second-hand Rubicon D44. Which is less than likely to happen where I live. I researched chrash JKR without luck and adds as well. If I am to put new axles, it'll be D60's but that wayyy further down the road
 
As I stated in the thread, no, not planning on going for D44 unless I find a good deal on second-hand Rubicon D44. Which is less than likely to happen where I live. I researched chrash JKR without luck and adds as well. If I am to put new axles, it'll be D60's but that wayyy further down the road
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Okay, just FYI. Don't run anything larger than 35's on that front dana 30 unless you want to kill it. And if you're going to wheel your rig moderately hard, then you're going to want to put in front chromoly full circle shafts and c gussets to reinforce it...then save up for your 60's if you must. And regearing, yea, just refer to that chart...you'll settle somewhere around that 4.10/4.56 range.
 
If it was me I would just go 4.88 and call it a day. I have been running 4.88s in a d30 with 35s and for a while now. That's my $.02 at least.
 
Mike_JK_Houston_711 said:
Okay, just FYI. Don't run anything larger than 35's on that front dana 30 unless you want to kill it. And if you're going to wheel your rig moderately hard, then you're going to want to put in front chromoly full circle shafts and c gussets to reinforce it...then save up for your 60's if you must. And regearing, yea, just refer to that chart...you'll settle somewhere around that 4.10/4.56 range.
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Thanks for the advices.

TennJK said:
If it was me I would just go 4.88 and call it a day. I have been running 4.88s in a d30 with 35s and for a while now. That's my $.02 at least.
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Good to know that someone is running this on their rig. How hard would you say you wheel it though, TennJK, on a scale from one to... Tenn? :cheesy: #DadJokes
 
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BenJKWrangler15 said:
Good to know that someone is running this on their rig. How hard would you say you wheel it though, TennJK?
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Well, everyone's opinions about how "hard" we wheel is completely subjective. I feel like I wheel on the more difficult side, but not crazy. I enjoy riding trails and crawling. I went with the 4.88 because the pinion is larger than the 5.13 pinion in the d30. When it comes to trail difficulties we normally do black diamonds (our trails are rated like ski slopes in the southeast). So take that for what it is[emoji106]🏼
 
TennJK said:
Well, everyone's opinions about how "hard" we wheel is completely subjective. I feel like I wheel on the more difficult side, but not crazy. I enjoy riding trails and crawling. I went with the 4.88 because the pinion is larger than the 5.13 pinion in the d30. When it comes to trail difficulties we normally do black diamonds (our trails are rated like ski slopes in the southeast). So take that for what it is[emoji106]🏼
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Done deal!
 
My gf's JKU has 35's and 4.88's on a 30 front and 44 rear and drives very nice in my opinion on the 3.8L engine and auto trans.
 
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