Speedo Recalibration For Larger Tire's

[Wrongway]

I have posted this question on another site with no knowledgeble response. I am running tire's on my truck that reqire the ABS to accept 00560, now I know that it will only accept a reading of 00601. I programmed the ABS to accept 00601, for 35" tire's, now I have 37x13.50x20 Toyo's that are rated @00560, my question is,I know that it can be done, as I have done it before, what will it take to recalibrate to get my driveability back. I think I played with the rim size, or rear-end ratio, or something, it's been so long. Thank you for any info.

[Keith Browning]

What scan tool are you using?

[Wrongway]

I forgot to include that, did'nt I. It is an NGS ODB2. I have the updated green card. Thank's

[Keith Browning]

Oops! Sorry for the delay..and nobody jumped in here. Don't you fleet guys have service manuals or access to on line manuals? I will say that it is hard to find the module configuration instructions if you are unfamiliar with the manual. Anyway FYI - NGS green card/ Service Card latest version as of today is V12.4 or V12.6

 

 

Hook- up and select the following successive menu choices:

• Service Bay Functions
• ABS
• Tire Size/Axle Ratio
• Year and Model
  • 99-02 F-Series / Superduty
  • 03-04 F-Series / Superduty

 

And from there you can select and change your

• Tire Size / Revs per Mile
• Tone Ring Size

[PowerstrokeRacer]

1) NGS with the Green Service card version 12.2.

 

2) Go to Service Bay Functions Press Trigger

 

3) Go to ABS Press Trigger

 

4) Go to Tire Size / Axle Ratio Configuration Press Trigger

 

5) Go to 99-02 F Series S-Duty Press Trigger

 

6) Go to Tone Ring Size (10.25) 120 teeth Press Trigger

 

7) Scroll down to (8.8) 108 teeth Press Trigger

 

8) Go to REV Per Mile and Press Trigger

 

9) Measure the Tire Circumferance in INCHES then Divide By 63360 That will give you the Rev Per Mile.

 

10) Multiply Rev Per Mile By 120, This is the Number of teeth per mile.

 

11) Divide the Number of Teeth Per Mile By 108 and use This number for your new Rev Per Mile.

 

P.S. If you still need more range you can use a 7.5" ring gear it has 102 teeth.

Hope this helps.