Considering the cost savings involved with building transmissions with just three shifting parts, you’ll understand why car companies have become very thinking about CVTs lately.
All this may sound complicated, nonetheless it isn’t. Theoretically, a CVT is much less complex when compared to a normal automatic transmission. A planetary gear automatic transmission - marketed in the tens of millions this past year - has a huge selection of finely machined moving parts. It provides wearable friction bands and elaborate digital and hydraulic handles. A CVT like the one referred to above has three simple moving parts: the belt and both pulleys.
There’s another advantage: The cheapest and best ratios are also additional apart than they would be in a typical step-gear transmission, giving the transmission a larger “ratio spread” This means it is a 
lot more flexible.
The engine can always run at the Variable Speed Transmission 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 just the right rpm for the right speed all the time.
As a result, rather than five or six ratios, you get thousands of ratios between your lowest (smallest-diameter pulley establishing) and highest (largest-diameter pulley establishing).
Here’s a good example: When you start from an end, the control computer de-clamps the insight pulley so the belt turns the smallest diameter while the output pulley (which goes to the wheels) clamps tighter to make the belt change its largest diameter. This generates the cheapest gear ratio (say, 3.0-to-1) for the quickest acceleration. As velocity builds, the computer varies the pulley diameters, as conditions dictate, to get the best balance of fuel economic climate and power.