Considering the savings involved in building transmissions with only three moving parts, you’ll understand why car companies have become very interested in CVTs lately.
All of this may audio complicated, but it isn’t. Theoretically, a CVT is much less complex when compared to a normal automatic transmission. A planetary equipment automatic transmission – offered in the tens of millions last year – has a huge selection of finely machined shifting parts. It offers wearable friction bands and elaborate electronic and hydraulic controls. A CVT just like the one referred to above has three simple moving parts: the belt and the two pulleys.
There’s another benefit: The lowest and greatest ratios are also further apart than they would be in a typical step-gear transmission, giving the transmission 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 the ideal rpm for the proper speed at all times.
As a result, rather than five or six ratios, you get an infinite number of ratios between your lowest (smallest-diameter pulley environment) and highest (largest-diameter pulley environment).
Here’s an example: When you start from an end, the control pc de-clamps the input pulley so the belt turns the smallest diameter while the result pulley (which goes to the wheels) clamps tighter to help make the belt switch its largest diameter. This produces the lowest gear ratio (say, 3.0-to-1) for the quickest Variable Speed Transmission acceleration. As rate builds, the computer varies the pulley diameters, as conditions dictate, for the best balance of fuel economy and power.