Abstract: Traction drive transmissions which may be utilized as speed increasers or speed reducers for various power and rotary motor applications including for use in transmissions for helicopter main rotor and tail rotor drives wherein power from the primary input source is transmitted to output shafts or driven elements which may be disposed at a variety of angular relationships with respect to the input source through multiple rollers which are shaped and in frictionally driven contact with one another so as to effectively divide the input load into multiple power paths to the output shafts or driven elements and wherein the rollers are oriented so as to reduce or eliminate the radial loading of stresses on the bearings in which the rollers are mounted.