CRF's Only Motorcycle Gearing Calculator

Please read disclaimer.

Bike:     (choose a bike and click 'Load')
Idle RPM:
Max RPM :
Max Torque RPM:
Max Power RPM:
Shift Down RPM:
Shift Up RPM:
Tire Size: / /
Tire Size (compare) / /  
Units: MPH     KPH
    
Ratios Driving   Driven     Ratio
Primary Drive: /      (between crank & clutch)
1st Gear: /    
2nd Gear: /    
3rd Gear: /    
4th Gear: /    
5th Gear: /    
6th Gear: /    
Jackshaft: /    (optional)
Final Drive: /    (stock)
Final (compare) /  
 
Various Data by Gear
 

RPM at xxx by Gear    (increment by xxx)

 

Calculations
Tire Circumference ( Width / 25.4 * Aspect Ratio / 100 + Rim Size / 2 ) * 2 * PI
Tire2 Circumference   
overallRatio  =  PrimaryDriveRatio * JackshaftRatio * GearXRatio * FinalDriveRatio
Calculate MPH from EngineRPM
MPH  =  EngineRPM / overallRatio * (TireCircumference/12) * 60/5280
MPH (simplified)  =  EngineRPM / overallRatio * TireCircumference * 0.000946969697
KPH  =  MPH * 1.6
Calculate EngineRPM from knownMPH
EngineRPM  =  KnownMPH * ((5280/60) / (TireCircumference/12)) * overallRatio
EngineRPM (simplified)  =  KnownMPH * 1056 / TireCircumference * overallRatio
EngineRPM for KPH  =  EngineRPM / 1.6
Welcome to CRF's Only gearing calculator. The information provided by this gearing calculator is provided "as-is" and without any claim for its accuracy. CRF's Only or YelTrik Motorsports, Inc. is in no way responsible for the accuracy or use of this information. By using this gearing calculator you accept these terms and are responsibility for the use of this information.

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