Considering the financial savings involved with building transmissions with just three shifting parts, you’ll realize why car companies have become very interested in CVTs lately.
All this may sound complicated, but it isn’t. Theoretically, a CVT is much less complex than a normal automated transmission. A planetary equipment automatic Variable Speed Transmission transmission – sold in the tens of millions last year – has a huge selection of finely machined moving parts. It provides wearable friction bands and elaborate digital and hydraulic controls. A CVT like the one explained above has three simple shifting parts: the belt and both pulleys.
There’s another benefit: The lowest and best ratios are also further apart than they would be in a conventional step-gear transmission, giving the tranny a greater “ratio spread” This means it is even more flexible.
The engine can always run at the optimum speed for power or for fuel economy, regardless of the wheel speed, which means no revving up or down with each gear 
change, and the ideal rpm for the proper speed at all times.
As a result, instead of five or six ratios, you get thousands of ratios between the lowest (smallest-diameter pulley environment) and highest (largest-diameter pulley setting).
Here’s a good example: When you start from an end, the control pc de-clamps the insight pulley therefore the belt turns the smallest diameter while the result pulley (which goes to the tires) clamps tighter to help make the belt switch its largest diameter. This creates the cheapest gear ratio (say, 3.0-to-1) for the quickest acceleration. As acceleration builds, the pc varies the pulley diameters, as conditions dictate, for the best balance of fuel economic climate and power.