Calculate Speed Based On RPM In Top Gear

Calculate Speed Based On RPM In Top Gear

Speed = (RPM × (TD*3.14159/12) × Sf × Pm) ÷ (Sr × Pc × G × 88.00)

Each revolution of the engine is reduced by the transmission gear ratio, each revolution of the output shaft of the transmission is reduced by the rear-end ratio, and each revolution of the tire makes the motorcycle move a distance equal to the circumference of the tire.

Example Presets

1985-1993 Big Twin, 1999-2001
Fuel Injected FLT 1994-2005 Big Twin
1994 Softail 1995-1999 Softail 1993-Softail 2006-2007 Dyna 2008-2016 Dyna 2007-2008 Touring 2009-2016 Touring 2007-2016 Softail 1995-1999 Softail with DD6
Note the 28t motor spocket 2017-Later Touring 2018 Softail

Guide

Fill in the blanks or choose dropdown options

Select Toggle Dropdown

• 300
• 500
• 700
• 1000
• 1500
• 2000
• 3000
• 4000

RPM: Revolutions per minute ?

Select Toggle Dropdown

• 61
• 65
• 66
• 68
• 70

Sr: Rear wheel sprocket tooth count (secondary drive) ?

Select Toggle Dropdown

• 36
• 37
• 46
• 50

Pc: Clutch sprocket tooth count (primary drive) ?

Select Toggle Dropdown

• Stock
• DD5
• OD6
• DD6
• DD7
• GrudgeBox

G: Transmission top gear ratio (last gear) ?

TDr: Rear tire diameter (include tire in measurement) ?

Select Toggle Dropdown

• 28
• 29
• 30
• 31
• 32
• 33
• 34

Sf: Transmission pulley or sprocket tooth count (secondary drive) ?

Select Toggle Dropdown

• 21
• 22
• 23
• 24
• 25
• 26
• 27
• 28
• 30
• 34

Pm: Motor sprocket tooth count (primary drive) ?

Speed MPH (Miles per hour)

Speed:

Calculate Speed