GearingCalculator

***************************************** DISCLAIMER *************************************
This software is supplied for interest only and is not intended for design purposes.
The author assumes no liability for any damages resulting from use of this software.
No warranty is offered, expressed, implied, or otherwise.
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Gearing Calculator

This spreadsheet calculates theoretical top speed for different input values of sprocket teeth and rear tire size.

Redline rpm and transmission gearing ratios may also be modified using the spreadsheet input cells. In general, these values will be constant. Modification is permitted to allow the calculator to be used for:

  1. Break in procedure (when “redline” is artificially limited)
  2. Motorcycle models other than the GS500

The user enters values for the rear tire size and the number of teeth on the front and rear sprocket. The resultant theoretical top speed for each gear is then calculated. The spreadsheet also generates plots of engine speed [rpm] versus theoretical motorcycle speed [km/h] or [mph] for each gear.

Engine speed for any motorcycle speed can be determined by iterating values in the Redline RPM. For example, to calculate the engine speed at 60 mph in top gear, keep changing the rpm value until the Theoretical Top Speed for 6th gear reads 60 mph. For this example, the solution is 4703 rpm. (NOTE: a quicker method for advanced Excel users is to use the “goal seek” function in the “Tools” drop-down menu).

Click here to download the calculator.

Gearing graphs for a stock GS500 are as follows:

km/h

mph