To use this Speed Calculator enter your Motor Sprocket, Axle Sprocket, Tire Circumference
(tire diameter x 3.14) and Engine RPM then hit "Calculate Speed" button. Gear Ratio and Speed will then be
Please keep in mind most engines run at a speed of 3,600 rpm when there is no load on the
engine shaft. However, when a load is applied to the engine shaft the engine speed decreases. The larger the load,
the greater the decrease. An engine with more horsepower will be affected less by the load and therefore be able to
operate at a higher rpm.
An axle sprocket with a larger diameter and more teeth will take off faster and have more
power, but will reach a slower top speed. An axle sprocket with a smaller diameter and fewer teeth will take off
slowly, but will reach a faster top speed. A smaller axle sprocket is closer to the size of the clutch sprocket and
therefore rotates closer to the same speed as the engine. Decide whether speed or power is more important to you
and choose your gearing accordingly.
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