regear or not to regear a 2012??? Here's the answer
JK Freak
Joined: Feb 2012
Posts: 988
Likes: 2
From: Middle Island, NY
i think most of you are not understanding how gears effect hp/torque. it does not change the output of the motor. gear ratios simply change the rpms at different speeds. if u run 35's or 37's with stock gears u are in the low rpm ranges all of the time and not taking advantage of the power. when u regear for larger tires u are putting the rpms in the sweetspot again to use the powerband of the motor. it is a no brainer here. regear if u want to regain theperformance lost after adding larger tires. stop blowing your money and do your gears.
someone was posting saying that a procal would not be necessary if going from stock 32's with 4.10's to 35's and 4.56's. this is wrong. a procal(or equivalent) will be 100% necessary for 2012+ when regearing to anything other than factory available ratios(the dealer can reprogram for 3.73's or 4.10's). as evo stated earlier...the jeep will go into limp mode and u will be stuck in second gear for autos. it MUST be reprogrammed.
someone was posting saying that a procal would not be necessary if going from stock 32's with 4.10's to 35's and 4.56's. this is wrong. a procal(or equivalent) will be 100% necessary for 2012+ when regearing to anything other than factory available ratios(the dealer can reprogram for 3.73's or 4.10's). as evo stated earlier...the jeep will go into limp mode and u will be stuck in second gear for autos. it MUST be reprogrammed.
1) 2012 6 speed Rubicon with 32 in Tires and 4:10 gears
2) 2012 6 speed Rubicon with 35 in Tires and 4:56 gears
both get the same exact gas milage.
both have generally the same RPM range in each gear.
My comment about not needing a procal for option number 2 was in reference to MPG's only and my experience with driving a stick not an auto. Still. even if you have an auto, you should not need a procal because your RPM ranges for each gear almost identicle to set up #1
JK Freak
Joined: Feb 2012
Posts: 988
Likes: 2
From: Middle Island, NY
I hope the below chart can put this issue to rest. check out the RPM ranges between the two different tires sizes and gears. I cant speak for Auto's but I dont know why it would go into Limp Mode. ITs an almost identicle set up.
JK Newbie
Joined: Sep 2011
Posts: 32
Likes: 0
From: Whitehouse, Tx
I have a 2012 JKUR auto, 35" KM2's, and had 4.10's stock. I drove it this way for 3-4 months and it was OK, but the power wasn't what it was stock. Even properly calibrated with a Procal, it never felt like it was in the right gear and the tranny was constantly hunting for the "sweet spot".
I had it regared to 4.88's and WOW! It's much more drivable, especially around town, and the tranny isn't always shifting between gears to find the "right" RPM.
Sure, the 3.6 has enough power to pull the 35's without being re-geared, but why sacrifice the power? Re-gear it and get back the power you've been missing
I had it regared to 4.88's and WOW! It's much more drivable, especially around town, and the tranny isn't always shifting between gears to find the "right" RPM.
Sure, the 3.6 has enough power to pull the 35's without being re-geared, but why sacrifice the power? Re-gear it and get back the power you've been missing
If you don't mind me asking, what brand gears did you put in? I'm going to get my 2012 regeared and haven't decided on a brand yet. I have 35" nitto trail grapplers and was thinking 4.56 but it sounds like you are real happy with your 4.88's.
Thread Starter
Sponsoring Vendor
Joined: May 2012
Posts: 1,423
Likes: 0
From: FULLERTON,CA
I can speak for the Autos, 6 Speeds, 2007-2011 , 2012 and Up. Hemi JK's. etc. We installed the very First gear set in a JK in 2006, Since then we have installed 100's of gear sets in JK's. We have most experience with regearing the JK out of anyone.
Gearing just does not just come down to a gear chart. You also have to consider the driving style of the person, future plans (maybe bigger tires) etc.. Not everyone will be satisfied with 4.56's on 35" tire with a 6 speed. Some may want the added pep of 4.88's or even 5.13's.
My point is with this thread, Just because it drives fine with stock gears doesnt mean you should'nt regear get your power back that it had stock.
Btw, the jeeps computer needs ratios needs changed to avoid the limp mode.
Gearing just does not just come down to a gear chart. You also have to consider the driving style of the person, future plans (maybe bigger tires) etc.. Not everyone will be satisfied with 4.56's on 35" tire with a 6 speed. Some may want the added pep of 4.88's or even 5.13's.
My point is with this thread, Just because it drives fine with stock gears doesnt mean you should'nt regear get your power back that it had stock.
Btw, the jeeps computer needs ratios needs changed to avoid the limp mode.
JK Freak
Joined: Feb 2012
Posts: 988
Likes: 2
From: Middle Island, NY
I can speak for the Autos, 6 Speeds, 2007-2011 , 2012 and Up. Hemi JK's. etc. We installed the very First gear set in a JK in 2006, Since then we have installed 100's of gear sets in JK's. We have most experience with regearing the JK out of anyone.
Gearing just does not just come down to a gear chart. You also have to consider the driving style of the person, future plans (maybe bigger tires) etc.. Not everyone will be satisfied with 4.56's on 35" tire with a 6 speed. Some may want the added pep of 4.88's or even 5.13's.
My point is with this thread, Just because it drives fine with stock gears doesnt mean you should'nt regear get your power back that it had stock.
Btw, the jeeps computer needs ratios needs changed to avoid the limp mode.
Gearing just does not just come down to a gear chart. You also have to consider the driving style of the person, future plans (maybe bigger tires) etc.. Not everyone will be satisfied with 4.56's on 35" tire with a 6 speed. Some may want the added pep of 4.88's or even 5.13's.
My point is with this thread, Just because it drives fine with stock gears doesnt mean you should'nt regear get your power back that it had stock.
Btw, the jeeps computer needs ratios needs changed to avoid the limp mode.
That being said, the only point I was trying to make is that for the 2007-2011 4:88 is the "typical" gear selected when adding 35's. Its different for the 2012 and later however. Where a person would use 4:88's, 4:56's are now that gear.
JK Freak
Joined: Oct 2011
Posts: 524
Likes: 2
From: Jacksonville, FL
Couple of questions?
I have always been told that you loose alot of durability in the Dana 30 when you jump from 4.88s up to 5.13s. Is this true?
Also it seems to me that by this chart that with 35s you should run 4.88s as it will put you just a hair under what a Rubicon's Rpm runs at stock. Is that correct?
Thanks
I have always been told that you loose alot of durability in the Dana 30 when you jump from 4.88s up to 5.13s. Is this true?
Also it seems to me that by this chart that with 35s you should run 4.88s as it will put you just a hair under what a Rubicon's Rpm runs at stock. Is that correct?
Thanks
Last edited by Blade; Oct 26, 2012 at 01:51 PM.
JK Freak
Joined: Feb 2012
Posts: 988
Likes: 2
From: Middle Island, NY
Couple of questions?
I have always been told that you loose alot of durability in the Dana 35 when you jump from 4.88s up to 5.13s. Is this true?
Also it seems to me that by this chart that with 35s you should run 4.88s as it will put you just a hair under what a Rubicon's Rpm runs at stock. Is that correct?
Thanks
I have always been told that you loose alot of durability in the Dana 35 when you jump from 4.88s up to 5.13s. Is this true?
Also it seems to me that by this chart that with 35s you should run 4.88s as it will put you just a hair under what a Rubicon's Rpm runs at stock. Is that correct?
Thanks
JK Freak
Joined: Oct 2011
Posts: 524
Likes: 2
From: Jacksonville, FL
Should I bump up to a 4.88 or would a 4.56 suit me just fine? This is my daily driver and it will not be going bigger on tires until my new axles are finished. I am still running the Dana 30 up front and don't wanna weaken it by going too big, as I have heard a 5.13 will do just that.
