Calculate Gear Ratios

Posted Sun, 04/05/2009 - 11:01 by administrator
Motorcycle Performance Guide

Calculate Gear Ratios

This program calculates the gear ratios of a motorcycle. The primary drive ratio and overall ratios for each gear are all calculated. Just enter the data in the white boxes below, then click the "Calculate" Button. Pressing the "Reset" button loads the default values into the form.

Engine Sprocket
Clutch Sprocket
Transmission Sprocket
Rear Wheel Sprocket

Primary Drive Ratio ( Engine to Transmission ) is calculated
Final Drive Ratio ( Transmission to Rear wheel ) is calculated
Overall Drive Ratio is calculated

Enter the Transmission ratio   Computed Overall Ratio  
1st gear  
2nd gear  
3rd gear  
4th gear  
5th gear Use a value of 1 if the bike does not have the gear
6th gear  

The reset values displayed are from a 1994 FXDL Harley-Davidson Dyna Low Rider. All late model Harley Big Twin models have similar. The Rear Wheel Sprocket can vary, with belt drive models using a 61, 65 or 70 tooth sprocket. Below is a table of typical values for late model Harley-Davidson motorcycles.

Ratios listed for all 2007 model HD's are overall ratios.

Make Model Engine Sprocket Clutch Sprocket Trans Sprocket Rear Wheel Sprocket 1st Gear 2nd Gear 3rd Gear 4th Gear 5th Gear 6th
Gear
HD
FLH
07-later		 34 46 32 66 9.312 6.421 4.774 3.926 3.279 2.790
HD
FXD
06-later		 34 46 32 66 9.312 6.421 4.774 3.926 3.279 2.790
HD
FLS models
07-later		 34 46 32 66 9.312 6.421 4.774 3.926 3.279 2.790
07-later Japanese 34 46 32 64 9.030 6.226 4.630 3.807 3.179 2.706
2008 HD EVO 1200 Sportster 38 57     9.315 6.653 4.948 4.102 3.517  
2008 HD EVO 883 Sportster 34 57     10.782 7.702 5.728 4.748 4.071  
HD FXDL Domestic 24 37 32 70 3.24 2.21 1.60 1.23 1.00  
HD FXDL Export 24 37 32 65 3.24 2.21 1.60 1.23 1.00  
HD FXDL Australia 24 37 32 61 3.24 2.21 1.60 1.23 1.00  
HD Drive Kit 40035-00
94-06		 25
Upgrade		 37
OEM		                
1996 HD EVO 883 Sportster 35 56 27 61 2.687 1.97 1.434 1.79 1.00  
1996 HD EVO 1200 Sportster 35 56 29 61 2.687 1.97 1.434 1.79 1.00  

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