Speedo Drive Gear

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Feb 12, 2001 | 01:17 AM

PAUL_2

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Speedo Drive Gear

Feb 12, 2001 | 02:04 PM

traildawg

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From: Lima, OH

Speedo Drive Gear

[font size="1" color="#FF0000"]LAST EDITED ON 12-Feb-01 AT 03:05 PM (EST)[/font][p]Is there a chart anywhere to help me determine what speedometer gear I need to get since I've changed gears & tire size? Stock I had 3.08 gears and 29 inch tires...but that's changed to 4.56 gears and 35 inch tires. Any help would be greatly appriciated.

TrailDawg
1993 F150 2WD
4.9L-Auto
Pro-Comp Stage-2 6" lift
Auburn Pro-Series Diff. w/4.56:1 gears
35x12.50x15 General Grabber MT's
Custom PreRunner front and rear bumpers

Feb 12, 2001 | 02:21 PM

paulg

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Speedo Drive Gear

You should be able to use the speedo gear for the current perceived gear/tire ratio you have now. Let me show you what I mean

New gear ratio * (Old tire size / New tire size) = perceived gear ratio:

4.56 * (29 / 35) = 3.77

So a speedo gear for a stock truck with 29" tires and 3.73s would be the speedo gear you need. If you have any questions let me know!!!!

Feb 12, 2001 | 02:48 PM

cgl

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From: NorCal

Speedo Drive Gear

[font size="1" color="#FF0000"]LAST EDITED ON 12-Feb-01 AT 03:48 PM (EST)[/font][p]On the 93, the speedometer is electric. Which means there is no gear to change like on the pre 92 trucks. It gets your speed from the ring gear in the rear diff. So if you change gears, the speedometer wont be affected. It's only affected if you change tire size.

Check out this post to find out how to do it:
https://www.ford-trucks.com/dcforum/80_96/3440.html