As the space between the pulleys and the length of the belt does not change, the two pulleys has to be adjusted (a single greater, another lesser) at the same time to keep up the correct quantity of tension around the belt. Easy CVTs combining a centrifugal drive pulley which https://gearboxcvt23210.bloggip.com/32727979/5-simple-statements-about-gearbox-cvt-explained