Jeep Wrangler Forum - Reply to Topic
Jeep Wrangler Forum

Go Back   Jeep Wrangler Forum > JK Jeep Wrangler Forum > JK General Discussion Forum > Gearing question

Join Wrangler Forum Today


Thread: Gearing question Reply to Thread
Title:
  
Message:
Post Icons
You may choose an icon for your message from the following list:
 

Register Now

In order to be able to post messages on the Jeep Wrangler Forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Additional Options
Miscellaneous Options

Topic Review (Newest First)
05-08-2012 08:03 AM
blackforestgreen i have the same gears, if you have the auto it will be fine for the size you are running, when i ruin the the gears, then i will up grade.
05-08-2012 07:21 AM
kjeeper10
Quote:
Originally Posted by Jervboy
So better gas mileage then? That I can understand because before I changed my tires, and even after, I think I get excellent gas mileage with my wrangler, consistantly 17-18 MPG all around and upwards of 21 on the highway. I just changed from the stock 255/75/R17 to dura tracs, 285/70/R17 and think I have noticed a slight decrease in the MPG but not much. This gearing thing is bothering me! So it will affect my rig offroad?
Your duratracs are a light tire which helps.

3.21's are not ideal but you will be fine off road. Remember, in 4wd the transfer case reduces the gear ratio too.
05-08-2012 05:50 AM
Jervboy So better gas mileage then? That I can understand because before I changed my tires, and even after, I think I get excellent gas mileage with my wrangler, consistantly 17-18 MPG all around and upwards of 21 on the highway. I just changed from the stock 255/75/R17 to dura tracs, 285/70/R17 and think I have noticed a slight decrease in the MPG but not much. This gearing thing is bothering me! So it will affect my rig offroad?
05-08-2012 05:34 AM
kjeeper10
Quote:
Originally Posted by Jervboy
All right, that I understand. Why then make the stock gear ratio 3.21 if it seems the better way to do it is a higher ratio?? Fuel economy? I don't really get it? My Jeep is a 6 speed manual, it sounds to me from what I am reading on the forum that the better gear ratios are higher, why then does the manufacturer put a 3.21 ratio in my Wrangler???
Easy answer.... Economy.

Not everybody mods/wheels their jeep.
05-08-2012 05:24 AM
Jervboy All right, that I understand. Why then make the stock gear ratio 3.21 if it seems the better way to do it is a higher ratio?? Fuel economy? I don't really get it? My Jeep is a 6 speed manual, it sounds to me from what I am reading on the forum that the better gear ratios are higher, why then does the manufacturer put a 3.21 ratio in my Wrangler???
05-07-2012 06:51 PM
JEEPDON
Quote:
Originally Posted by Jervboy View Post
Found it. 3.21 rear axle ratio. Now what does that mean versus the 4.1?
3.21 = Transmission output shaft turn 3.21 revolutions per 1 revolution of rear axle
4.10 = transmission output shaft turns 4.10 revolutions per 1 revolution of axle.
The faster the output shaft turns in relation to the axle; the greater your mechanical advantage. Also, while having greater mechanical advantage, you will also be running your engine closer to its "sweet spot". I.E. higer torque and HP output to rear wheels. So your lower gears( higher numerical value) almost gives you a "double whammy"!
05-07-2012 12:14 PM
MTH
Quote:
Originally Posted by Jervboy View Post
Found it. 3.21 rear axle ratio. Now what does that mean versus the 4.1?
It means that at the same speed on the same size tires and in the same gear, you'll be spinning ~500 or so less RPMs than somebody with 4.10 gearing.

Because your engine puts out more torque and more horsepower the more RPMs you spin until you hit redline, this means that the jeep with the 4.10 gearing will feel "peppier" at the same speed--it would hold speed better and feel as if it's got more "get up and go" when you push the pedal. It will also be easier on the clutch in that it will lug less when you start.

You can "simulate" the first benefit (higher RPMs at a given speed) by simply waiting until you reach higher RPMs to shift gears (3k+) and not using 6th gear anymore. You can't simulate the second benefit (easier on the clutch).
05-07-2012 12:07 PM
kjeeper10
Quote:
Originally Posted by Jervboy
Found it. 3.21 rear axle ratio. Now what does that mean versus the 4.1?
Stock size tires no bigger
05-07-2012 11:51 AM
Jervboy Found it. 3.21 rear axle ratio. Now what does that mean versus the 4.1?
05-07-2012 11:40 AM
Jervboy
Gearing question

Dumb question but how do I find out what gearing I have?? I don't know, I'm an idiot! 2011 JKU Sport S, six speed manual transmission, V-6.

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -5. The time now is 05:21 PM.



Jeep®, Wrangler, Liberty, Wagoneer, Cherokee, and Grand Cherokee are copyrighted and trademarked to Chrysler Motors LLC.
Wranglerforum.com is not in any way associated with the Chrysler Motors LLC