CVTs! First off, I tested out some CVT designs that used cones and belts to achieve a continuously variable gear ratio. While these designs were very elegant, they all began to slip when I applied any significant resistance to the output, and the use of rubber belts meant they also had quite a lot of friction.

This led me to creating a CVT that used size-changing wheels to vary the gear ratio. This completely removed the slipping problems as it allowed me to use a chain to transmit power rather than a rubber belt. After testing out this new CVT, the idea struck me that the design had a lot of potential to work well as an automatic transmission. So, after some modifications to the design, I managed to create an automatic continuously variable transmission. Enjoy the video!