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Old 05-22-2012, 02:12 AM   #1
walka
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Speedo help

Iv'e just changed from stock wheels and tires to 20" rims with 35 profile tires, It's has 3.44 gears and a T350, The Speedo is out about 20 MPH , It has a Red Speedo Gear Any one know which color I should have?
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Old 05-22-2012, 02:14 AM   #2
Mrknowitall
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Re: Speedo help

Quote:
Originally Posted by walka View Post
Iv'e just changed from stock wheels and tires to 20" rims with 35 profile tires, It's has 3.44 gears and a T350, The Speedo is out about 20 MPH , It has a Red Speedo Gear Any one know which color I should have?
http://tri-5.chevyrides.com/speedo.php
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Old 05-22-2012, 02:59 AM   #3
walka
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Re: Speedo help

No good, carn't load in 20" , The 20 MPH is fast
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Old 05-22-2012, 03:03 AM   #4
Mrknowitall
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Re: Speedo help

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Originally Posted by walka View Post
No good, carn't load in 20" , The 20 MPH is fast
hummm.... then idk, someone here years ago had a chart that converted rim size to 15in rim with tire size to equal 20's but i cant find it...... wait till tomoro when everyone is awakle im sure ull get ur answer, alot of guys run 20s here.

sorry!
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Old 05-22-2012, 06:12 AM   #5
walka
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Re: Speedo help

Great , thanks
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Old 05-22-2012, 07:22 AM   #6
Keith Seymore
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Re: Speedo help

I'd figure out how much you are off, in percentage (by pacing with a GPS) and then throw an external adapter on there -

http://www.partshp.com/speedometer_gears.htm

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Old 05-22-2012, 09:48 AM   #7
hatzie
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Re: Speedo help

Try this Excel 2003 Spreadsheet. It calculates RPM and Speedometer gear information including ratio adapters based on transmission, Transfer Case, axle ratio, & tire sizes.
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File Type: zip RPM_Gear_Axle_Transmission_TransferCase.zip (58.6 KB, 42 views)
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Old 05-22-2012, 09:53 AM   #8
gchemist
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Re: Speedo help

Plug your info into this calculator. http://www.tciauto.com/tc/speedometer-gear-calculator

Change the drive and driven gear ratio until you find a combo to the closest whole number. You may have to change the housing if you change the driven gear too much.
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