Today I have the privilege to hold in my hands something special. It is called Ratio Zero and it is the worlds first operational gear based cvt But before I explain how this piece of mechanical poetry actually works allow me to first explain why a gear based CVT is a big deal. As you probably know CVT stands for continuously variable transmission and from the perspective of fuel efficiency, smoothness and ease of use they are the ultimate transmission. And while I would not choose a CVT transmission for a vehicle that I want to take to a twisty mountain road or to the track where I want to enjoy revving the engine out through the gears, I would gladly choose a CVT for a vehicle that I drive everyday on the highway or in boring stop-and go commuter traffic. A traditional manual or automatic transmission has a set number of gear ratios or speedsFor example, a gear ratio of 3.6:1 tells us that for every 3.6 revolution of the engine, the wheels only make one revolution while the torque at the wheels is increased 3.6 times. So the frist gear reduces vehicle but increases torque, this is why it’s used for getting the vehicle moving from a standstill and top climb steep hills. A manual or automatic transmission will usually have anywhere between 4 to 8 such gear ratios which we call speeds. Compared to this a CVT will only have two “gear ratios” or speeds. This is because a cvt does not have gears Instead we have two conical pulleys and a belt or chain running around them. We slide the belt along these pulleys and the different sizes of the pulleys at different parts of the cone simulate an endless number of different gear sizes which means that a CVT has an endless number of ratios in this range between its lowest and highest ratio. So if an automatic or manual is a 6 speed or 7 speed or whatever than a CVT is a million speed transmission or an infinite number of speeds transmission. Ok, if CVTs are so great why aren’t they more popular? Why aren’t they on every car, truck, motorcycle, bicycle? Well, that’s because traditional CVTs, they kinda suck. Their first problem is that although they help the engine be more efficient, they themselves are not very efficient at all and that’s because friction is at the very core of the design of a CVT. If you observe the inner workings you will see that torque is transferred between the pulleys by a belt or a chain. The belt or chain has nothing to grip onto, there are no gear teeth, no notches, no grabbing points, which means that the belt tension or the friction between the belt itself and the smooth surface of the pulley cone are the only thing transferring the torque. Which means that to transfer substantial amounts of torque we need substantial friction and as we know friction leads to efficiency losses, heat and wear. This is why a typical belt or chain CVT in a car is around 80-88% efficient, a more simple scooter CVT is around 70-75% efficient whereas a geared manual transmission is 95-97% efficient in almost all applications. This is why researchers, inventors and many others have been trying to create a transmission that combines the smoothness, ease of use, fuel efficiency and continually variable gear ratios of the CVT with the torque capacity and low friction of a geared transmission.Despite repeated efforts there has been little success, until in 2016 a man named Edyson Pavlicu had a breakthrough idea - to split the rotation and create the world's first geared CVT transmission - Ratio Zero.
