Abstract: An example traction drive includes a first ring having an inclined surface that is inclined at a first angle; a second ring having a respective inclined surface that is inclined at a second angle different from the first angle, such that the inclined surface of the first ring and the respective inclined surface of the second ring form a groove; a third ring disposed opposite to the first ring and the second ring, and having a respective groove disposed on a surface of the third ring; and a plurality of rollers disposed between, and configured to roll within, (i) the groove formed by the inclined surface of the first ring and the respective inclined surface of the second ring, and (ii) the respective groove of the third ring.