Gearless scooters have automatic transmission known as Continuously Variable Transmission (CVT) which enables it to automatically shift from low to high drive ratios using centrifugal systems.This video explains the working of a Gearless Scooter’s Transmission System with relevant animations.
As we’ve mentioned, most scooters use a specific type of automatic transmission called a Continuous Variable Transmissions. A CVT is different from other transmissions in that it doesn’t use separate gears to create different gear ratios. Instead, the CVT in a scooter consists of two pulleys connected by a v-belt.
One of these pulleys is connected to the engine, while the other is connected to the scooter’s driven wheel.Since the v-belt rides on the slopes of the pulley cones, this means that pushing the cones together effectively creates a larger diameter pulley while pulling them apart creates a smaller pulley.
When the Input Pulley is becomes smaller and the output pulley becomes larger translates into a lower ratio which is the number of times the shaft spins for every revolution of the engine, hence a ratio. While the scooter gathers momentum and accelerates, the pulleys keep varying their diameters and lower the engine speed (RPMs) for relaxed cruising or climbing up the revs for quick overtaking.