In all my years of building these machines, I have NEVER seen a sucsessful/reliable friction drive, possibly with the exeption of weapons drive on a couple of serious American spinners. (F-Bomb, being a case in point)
Believe me, there is no substitute for a well designed and engineered transmision using spur/planetery gears, chains & sprockets or belts & pullies, or a combination of some or all of the above.