This second type of design is analogous in theory to the pulley-based mostly CVT but nevertheless slightly distinct. The sections included here are energy rollers and discs, rather than pulleys and belts. There's two disks involved with two rollers between. The design principle dates again to ahead of the 1930s, https://gearbox-cvt40470.activablog.com/31935493/the-best-side-of-gearbox-cvt