Have 33's with 3.21's and looking to regear.....

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rhodesking

New member
So I have a 2012 JKU auto with 3.21's. I am currently running 33's and cant decide whether to jump up to 4.10's or 4.56's. I think 4.88's would be overkill for me, I dont do a ton off-roading. Plus, its my DD so am looking for decent mileage on the highways. Anybody's thoughts or input that is running either of those gears with 33's would be great. Oh yeah, new to the forum so thanks in advance for any info.:rock:
 
wayoflife

wayoflife

Administrator
Staff member
Are you planning to keep your 33's or do you think you'll go bigger some day? Also, when you installed your 33's, did you make sure to properly recalibrate your speedometer?
 
R

rhodesking

New member
There's a slight chance I may move up in size. I did not recalibrate speedo as I went from a 32.5's to 33's and read in forums that it was such a small difference that wasnt worth the money to buy the AEV ProCal. But even before I upgraded the tires, going up hills, etc used to drive me crazy that it wouldnt drop down a gear unless I put it to the floor. I want to keep in mind that I also will be towing snowmobiles, camper, and fishing boat around at times. I do plan to have shop recalibrate speedo, etc for whatever gears I do move forward with. I'm leaning towards 4.10's, but a Jeep shop that I talked to said they would go 4.56.
 
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jkmadness

New member
rhodesking said:
So I have a 2012 JKU auto with 3.21's. I am currently running 33's and cant decide whether to jump up to 4.10's or 4.56's. I think 4.88's would be overkill for me, I dont do a ton off-roading. Plus, its my DD so am looking for decent mileage on the highways. Anybody's thoughts or input that is running either of those gears with 33's would be great. Oh yeah, new to the forum so thanks in advance for any info.:rock:
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just did mine to 4.56 and i love it,mine is a 2012 auto and i have 33 nittos 295/70/17...you will be set for down the road moving up to 35's
 
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jkmadness

New member
rhodesking said:
There's a slight chance I may move up in size. I did not recalibrate speedo as I went from a 32.5's to 33's and read in forums that it was such a small difference that wasnt worth the money to buy the AEV ProCal. But even before I upgraded the tires, going up hills, etc used to drive me crazy that it wouldnt drop down a gear unless I put it to the floor. I want to keep in mind that I also will be towing snowmobiles, camper, and fishing boat around at times. I do plan to have shop recalibrate speedo, etc for whatever gears I do move forward with. I'm leaning towards 4.10's, but a Jeep shop that I talked to said they would go 4.56.
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if you have a 2012 auto and up ,you will need the procal when you regear otherwise the tranny will go into limp mode:twocents:
 
wayoflife

wayoflife

Administrator
Staff member
rhodesking said:
There's a slight chance I may move up in size. I did not recalibrate speedo as I went from a 32.5's to 33's and read in forums that it was such a small difference that wasnt worth the money to buy the AEV ProCal. But even before I upgraded the tires, going up hills, etc used to drive me crazy that it wouldnt drop down a gear unless I put it to the floor. I want to keep in mind that I also will be towing snowmobiles, camper, and fishing boat around at times. I do plan to have shop recalibrate speedo, etc for whatever gears I do move forward with. I'm leaning towards 4.10's, but a Jeep shop that I talked to said they would go 4.56.
Click to expand...

I've never heard of a 32.5" tire. Are you referring to a metric equivalent? Any time you change tire sizes, you NEED to recalibrate your speedometer as IT controls your shift points. Failure to do so will cause your Jeep to feel like it's got less power than it really does. I'm not saying that you'll see leaps and bounds of a difference but, running 33's on 3.21's and on a 3.6L motor shouldn't feel that bad. I run 37's on factory 4.10's on my 2012 JK and that's a much bigger jump in size. With the speedo calibrated, it isn't bad at all.

There is A LOT of really bad information on the internet and you can believe it if you want. I'm just trying to save you some money. Regearing for just a set of 33's would be a hard thing for me to do.
 
R

rhodesking

New member
wayoflife said:
I've never heard of a 32.5" tire. Are you referring to a metric equivalent? Any time you change tire sizes, you NEED to recalibrate your speedometer as IT controls your shift points. Failure to do so will cause your Jeep to feel like it's got less power than it really does. I'm not saying that you'll see leaps and bounds of a difference but, running 33's on 3.21's and on a 3.6L motor shouldn't feel that bad. I run 37's on factory 4.10's on my 2012 JK and that's a much bigger jump in size. With the speedo calibrated, it isn't bad at all.

There is A LOT of really bad information on the internet and you can believe it if you want. I'm just trying to save you some money. Regearing for just a set of 33's would be a hard thing for me to do.
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They were 255/75/17, which as I'm sure you know equivalent to 32". I hear ya about info on the internet. I'll def check out getting recalibrated. Thanks for your input, greatly appreciated.
 
gtony12

gtony12

Caught the Bug
wayoflife said:
I've never heard of a 32.5" tire. Are you referring to a metric equivalent? Any time you change tire sizes, you NEED to recalibrate your speedometer as IT controls your shift points. Failure to do so will cause your Jeep to feel like it's got less power than it really does. I'm not saying that you'll see leaps and bounds of a difference but, running 33's on 3.21's and on a 3.6L motor shouldn't feel that bad. I run 37's on factory 4.10's on my 2012 JK and that's a much bigger jump in size. With the speedo calibrated, it isn't bad at all.

There is A LOT of really bad information on the internet and you can believe it if you want. I'm just trying to save you some money. Regearing for just a set of 33's would be a hard thing for me to do.
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:thinking: If you don't have a tool to set or recal the speedo, do you have to go to the dealer to have it done???? :idontknow::idontknow::idontknow:
 
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RockyJk

RockyJk

Active Member
gtony12 said:
:thinking: If you don't have a tool to set or recal the speedo, do you have to go to the dealer to have it done???? :idontknow::idontknow::idontknow:
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Dealers only recalibrate to factory sized tires i think

Sent from my DROID RAZR using WAYALIFE mobile app
 
wayoflife

wayoflife

Administrator
Staff member
rhodesking said:
They were 255/75/17, which as I'm sure you know equivalent to 32". I hear ya about info on the internet. I'll def check out getting recalibrated. Thanks for your input, greatly appreciated.
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Yeah, 255 is the metric equivalent of a 32" tire but I can assure you that the actual measurement will be closer to 30". Your new 33's will be more like 31.5". That's enough of a difference to matter.
 
J

jkmadness

New member
rhodesking said:
They were 255/75/17, which as I'm sure you know equivalent to 32". I hear ya about info on the internet. I'll def check out getting recalibrated. Thanks for your input, greatly appreciated.
Click to expand...

if you decide to buy the procal and do it yourself make sure you measure from the center of the wheel down to the ground and double that measurement...that should be the number to use to calibrate.
 
gtony12

gtony12

Caught the Bug
wayoflife said:
Yeah, 255 is the metric equivalent of a 32" tire but I can assure you that the actual measurement will be closer to 30". Your new 33's will be more like 31.5". That's enough of a difference to matter.
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If you don't have a tool to set or recal the speedo, do you have to go to the dealer to have it done????
 
wayoflife

wayoflife

Administrator
Staff member
gtony12 said:
If you don't have a tool to set or recal the speedo, do you have to go to the dealer to have it done????
Click to expand...

Your dealership can only recalibrate your tires up to a 255 or a 32" tires. Anything bigger cannot be done on their end and you will need an AEV ProCal or the like to do it.

As mentioned, it is important to measure your tire's diameter correctly and that is to either measure from the ground to the edge of the shoulder (the corner where the sidewall becomes the tread) or, from the center of your wheel to the ground and multiply that by 2.
 
EstianSwanepoel

EstianSwanepoel

Member
I have an '11 Auto JKUR.. I want to run 285s.. However everyone keeps telling my my mpg will go to **** and so will the power. But none of them have recalibrated their jeeps with 285s..

Surely it can't be that bad. They're not even that much bigger than stock and I want to run all terrains.
How close to stock drive will recalibration get my drive? Obviously there will be some loss of mpg but it can't be as terrible as everyone makes it out to be..
 
MeatHead

MeatHead

New member
I just inquired my Offroad shop about new gears the other day for my 09 Jk. I'm running 35" mud terrains on stock gears. I have the AEV procal. But my jeep shifts in and out of overdrive a lot. I thought 4.88 ring and opinions would be fine but the shop wants to put 5.13's in. Are they trying to burn me? This is my daily driver and I have to drive across the country in a week.
 
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