speedometer gear

:read2:

727 Push Button = 8 Drive Teeth
727 Non Push Button = 13 Drive Teeth
904 Non Push Button = 13 Drive Teeth
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Drive Teeth x Rear End Gear Ratio x Tire Revolutions Per Mile
1001 = Gear Teeth
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Tire Revolutions Per Mile = 20168 _
Tire Height
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Tire Revolutions Per Mile Quick Reference

24” = 840.3 Tire RP Mile
25” = 806.7 Tire RP Mile
26” = 775.7 Tire RP Mile
27” = 746.9 Tire RP Mile
28” = 720.3 Tire RP Mile
29” = 695.4 Tire RP Mile
30” = 672.3 Tire RP Mile

example

13 x 4.56 x 683.7 (20168 ÷ 29.5 [tire height] )
Drive Teeth Rear End Ratio Tire Revolutions Per Mile

Divide Answer by 1001, Gives number of teeth needed on gear.