Speedometer Gear
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Speedometer Gear
I Just Put 4.56 Gears In My Truck And I Was Wondering What Speedometer Gear I Should Use. Don't Have A Clue Where To Begin! Stock Gear Were 3.08's With A Yellow Speedo Gear If That Helps Anyone.
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From: Suffolk, VA USA
What was the original tire size on the truck? Also, did you have the 36s on the on with the 18 tooth (yellow) gear, and if you did how far off was the speedometer? I need this info to figure out what drive gear you have.
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The Original Tire Size Was A 30 Incher. I Did Have The Original Gear With The 36 And 3.08 Combo And It Was Off Anywhere Between 5-15 Mph Off. Depending On How Fast I Was Going. I've Been Using My Gps To Get Around With. Don't Want No Tickets From The Po Po!
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From: Suffolk, VA USA
Looks like you have an 8 tooth drive gear, so a 21 tooth (red) speedometer gear will do it for you.
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What Would It Be If It Happens To Be The White Gear That I Have? I'm Starting To Second Guess Myself On Having The Yellow. Its Been Awhile Since I Last Pulled It Out!
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From: Suffolk, VA USA
It may not make any difference. I based my original calaulations on your truck coming from the factory with 3.08 gears and 235/75/15 tires, which led to an 18 tooth (yellow) gear matched to an 8 tooth drive gear. 3.08 gears and 30 inch tires leads to a 17 tooth (white) gear matched to an 8 tooth drive gear. If your speedometer was accurate with 30 inch tires, someone likely already corrected the speedometer gear to match the larger tires. Those numbers were important for figuring out which drive gear you have. The drive gear is the one the turns the speedometer gear. With an 8 tooth drive gear, you need a 21 tooth (red) speedometer gear to match the 4.56 gears.
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Seems More Than 5%. I'm Not Sure About Having The Speedo Calibrated. I Bought The Truck Already Lifted. I'm Just Going Through The Whole Truck And Making Everything Right. The Way It Should Have Been Done In The First Place. But If I Had To Guess It Was Never Calibrated By The Individual Who Owned It Before Myself. Thanks For All The Usefull Info! Really Appreciate It!
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See if your truck still has the original sticker in the drivers side door jamb that says what size tires the truck came out of the factory with....if they are 235/75/15 this all info should is good.
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Originally Posted by WATTSUP!
Seems More Than 5%. I'm Not Sure About Having The Speedo Calibrated. I Bought The Truck Already Lifted. I'm Just Going Through The Whole Truck And Making Everything Right. The Way It Should Have Been Done In The First Place. But If I Had To Guess It Was Never Calibrated By The Individual Who Owned It Before Myself. Thanks For All The Usefull Info! Really Appreciate It!
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From: Suffolk, VA USA
The simple formula doesn't work because there was also a change in the tire size...the original gearing was based on a stock 235/75/15 tire, which was about 29 inches in diameter. The new tire size is 36 inches. The tire size is another variable.
Last edited by ri_truck_guy; May 8, 2007 at 05:36 AM.