Gearing / RPM / KPH Calculator
The gear ratio and speed/RPM info for the different drive sprocket options available are below.
Remember there are variations in tyre sizes and wear will also affect actual readings so this is a guide only.
You can enter your own sprocket and tyre sizes to check the effect on gearing.
Wheel revolutions per minute
RPM / Primary Drive Ratio * Gear Ratio / Final Drive Ratio
EU Tire Circumference (metres)
( Width * Aspect Ratio / 100 + Rim Size * 25.4 / 2 ) * 2 * PI / 1000
Speed in KPH
Wheel revolutions per minute * Tire Circumference * 60 / 1000
1 - The error NaN means Not a Number. Basically an invalid result, re enter the values & recalculate.
2 - The early F650GS manual rounded gearing values to 2 decimal places so the figures look different.
1 - The Husqvarna Terra gear ratio's are the same and the calculator is correct for the ABS model.
2 - The non ABS Terra has an 18" wheel, manually enter the wheel/tyre size and the calculator is correct.