What gears do I have in my axles? - Page 3 - JeepForum.com
LinkBack Thread Tools
post #31 of 31 Old 06-18-2013, 07:39 AM
Registered User
2009 JK Wrangler 
Join Date: Oct 2012
Posts: 193
Originally Posted by ronjenx View Post
Remember, you were describing how the computer determines what speed is to be displayed on the speedometer.

All the computer needs to know is distance per tire revolution ( for the miles part), and how long it takes to make one revolution (for the per hour part). It gets this data from the ABS tone rings.

If what you say is true, the mph would be wrong when coasting downhill with the engine at idle; when the automatic's torque converter is slipping; when either transmission is in a gear other than top gear, (if top gear is what is assumed); etc.

As mentioned in a previous post, people who change gear ratios and don't reprogram, don't see a different error in the speedometer.

A 30" tire travels about 7.85 feet per revolution.
That's about 672.6 revolutions per mile.
If the tire rotates at a rate of 672.6 times per minute, the speedometer will show 60 mph.
I don't see any gear ratio or engine rpm data in that.
Yep. You're right. I'm trying to incorrectly join what the computer does and the old fashioned method. My apologies.

Rtone1583 is offline  
Sponsored Links

Quick Reply

Register Now

In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.

Email Address:


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.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page

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
Trackbacks are Off
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome