Considering the financial savings involved in building transmissions with only three moving parts, you’ll understand why car companies have grown to be very thinking about CVTs lately.
All of this may audio complicated, but it isn’t. Theoretically, a CVT is far less complex than a normal automatic transmission. A planetary gear automatic transmission – sold in the tens of millions last year – has a huge selection of finely machined moving parts. It offers wearable friction bands and elaborate electronic and hydraulic settings. A CVT just like the one defined above has three fundamental shifting parts: the belt and both pulleys.
There’s another benefit: The cheapest and best ratios are also additional apart than they would be in a typical step-gear tranny, giving the tranny a greater “ratio spread” This 
means it is a lot more flexible.
The engine can always run at the optimum speed for power or for fuel economy, whatever the wheel speed, this means no revving up or down with each gear change, and just the right rpm for the proper speed constantly.
As a result, Variable Speed Transmission instead of five or six ratios, you get thousands of ratios between the lowest (smallest-diameter pulley environment) and highest (largest-diameter pulley establishing).
Here’s an example: When you start from an end, the control computer de-clamps the input pulley so the belt turns the smallest diameter while the result pulley (which would go to the wheels) clamps tighter to help make the belt convert its largest diameter. This produces the cheapest gear ratio (say, 3.0-to-1) for the quickest acceleration. As velocity builds, the pc varies the pulley diameters, as conditions dictate, for the best balance of fuel economy and power.