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4.10 vs 4.56

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Old 11-19-2015 | 09:49 AM
  #11  
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They sell JKs with 32s and 4.10. Logic would tell you that 4.56 and 35s would be a good combo. There is no downside to that combo. The upside is that it will be cheaper. 4.10 gears are more expensive as you have to buy OEM gears (at least that has always been the case).
Old 11-19-2015 | 10:08 AM
  #12  
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I found the factory 4.10 gears on the rubicon's 32's to be very low for daily driver purposes. Works excellent off-road though but not as well on the highway. My take on it is if you're mostly on the street then 35's with 4.10's would be a good combo. If you off-road more than the average joe, then 4.56's would be my choice.
Old 11-19-2015 | 11:34 AM
  #13  
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Originally Posted by Flynlo
I found the factory 4.10 gears on the rubicon's 32's to be very low for daily driver purposes. Works excellent off-road though but not as well on the highway. My take on it is if you're mostly on the street then 35's with 4.10's would be a good combo. If you off-road more than the average joe, then 4.56's would be my choice.
Well, with 4.56 you end up about the same as a stock rubi on 4.10s. Except, you have a lot more rotating mass to turn. In addition, these JKUs can get heavy. Again, there is no loss to going 4.56 vs. 4.10 on 35s. Gas mileage will be nearly the same. Possibly better with the 4.56. I have a 2013 JK and on 35s was getting 18 mpg (hand calculated). Went to 37s on beadlocks and 4.88s. Gas mileage for that was 18.2. It takes x amount of HP to turn the tires. With larger tires, it takes more power. So, you don't want to be at the stock RPM at 70, you want to be higher where it is more efficient.

Also, I had 3.73 gears with 35s and it sucked. I lived with it like many do. I drove a 2014 with 4.10s and 35s for a while and it was manageable. However, it was a super light manual 2-door. And the tires were technically 34".

Not worth the money to regear to 4.10 for 35s.
Old 11-19-2015 | 12:52 PM
  #14  
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I would agree with some of the sentiments expressed, saying that 4.56 gears with 35s would be a great combo. The power band isn't vey big with these mid-sized V6 engines. A couple hundred RPM can make a huge difference in driveability and fuel mileage.

Our '13 JKUR was ordered with 4.10 gears. I installed a Rock Krawler 2.5 X-Factor Long Arm Kit, JCR bumpers front and rear, Warn 9.5 Powerplant winch, PSC aluminum Crusher flares, and a Wild Boar fastback hardtop. It would tend to hunt gears on even modest hills... especially in a head wind. We spend a fair amount of time in the mountains, Death Valley, and around Las Vegas.

Our factory 32s bit the dust recently and I put 37" Goodyear MTR w/Kevlar tires and Method 105 Beadlocks on. I have a set 5.13s ready to install but am waiting for my buddy who knows Dana stuff better than me to have time to help me out. Of course, 37s with the 4.10 gears has made the driveability worse... not bad on flat/no wind but dramatic for sure. I can tell you from a fuel mileage standpoint that the Superchips Flashpaq programmer's 87 Octane fuel mileage program certainly made a huge difference. I was getting about 18.8 mpg before the 37s and am still getting about 17.6 since the swap and the programming. Will be anxious to see the effects once the 5.13s are installed and it won't work the motor as hard or hunt for gears.
Old 11-19-2015 | 12:56 PM
  #15  
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I am happy with my 4.56 and 35. Glad I didn't go 4.88. I posted this and found it very useful when making a decision.

https://www.jk-forum.com/forums/modi...s-only-295280/

Last edited by WINGIT; 11-19-2015 at 12:59 PM.
Old 11-19-2015 | 01:51 PM
  #16  
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'14 auto, 4.56s, 35s...I would go with at least 4.56s. When I switched from 3.73s to 4.56s I expected a little more punch than I got. Adding a 91 octane boost program from flashpaq got me there but the 4.56s alone did not. YMMV.

Last edited by 14Sport; 11-20-2015 at 03:11 AM.
Old 11-19-2015 | 04:07 PM
  #17  
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I have 4.56 and 35" MTRK's. It's the perfect gear for those tires with the 3.6 imo. I have an auto. With the manual, 4.88 might be a good combo.
Old 11-19-2015 | 05:37 PM
  #18  
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Originally Posted by WHT_JKUR
I have 2014 JKUR manual on 35s as well, Swapped 4.10s for 4.56. Got me back to stock rubi ratio. Here is a handy calculator.. That will give you info on rpm and speed, based on gears and transmission.. Allows you to do side by side comparison http://www.grimmjeeper.com/gears.html
All this said there have been a couple times off-road (4-high) I wish I went 4.88, but when I am on a road trip doing 80, glad I stayed went 4.56. My logic is I can use 4low if I need more off-road grunt
Old 11-19-2015 | 09:13 PM
  #19  
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Originally Posted by Invest2m4
Also, I had 3.73 gears with 35s and it sucked. I lived with it like many do. I drove a 2014 with 4.10s and 35s for a while and it was manageable. However, it was a super light manual 2-door. And the tires were technically 34".

Not worth the money to regear to 4.10 for 35s.
I was initially running 3.21's with 33's (true 32's) and it was manageable, at best. My JK, like yours was, is a 2 door and I try to keep it as light as possible. Manual Trans, factory bumpers, lightweight tire carrier, ect. I opted for the 4.10's for a few reasons.
1. This isn't my final JK. When eventually I trade this one in and get a 4-door, I'll be taking everything aftermarket with me to the new one and returning the 2 door to stock. If I had installed 4.56 and put on factory sized tires, it would have been geared far too low.
2. According to the gear ratio chart that floats around the inter webs, my '14 JK w/ the 3.6L, Manual trans and 35's (True 34's) put me right in the middle of the "Green" zone with 4.10's
3. I only off-road a few times a month so the slightly higher gear ratio works better for me for city and highway driving.

When I get a 4-door and run 35's I'll put in 4.56 at a minimum.
Old 11-22-2015 | 07:32 AM
  #20  
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I have a 2012 that's a 2 door manual and running 35 nittos trial grappers. I regeared to 4.56 and it is perfect, maybe geared a little to low. You won't be disappointed with 4.56 or even 4.10 gears but 4.88 might be a little to low unless 37's are in the future.



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