Wa-a-ay back (1970s?) I had one of those little shiny jobbies with the metal star wheel and a post clamped to the spoke. It was fine most of the time but every now and again on a fast descent I would occasionally get a >>CLUNK!<< in the middle of the clicks. Careful checking of the various alignments would appear to be correct. I finally decided it might be inertia carrying the star wheel a bit past where the post left it and the post would hit right on the tip of the star on the next pass. It was rather unnerving -- visions of the unit plummeting into the spokes and away I go. So I far preferred the Huret belt drive when I discovered it. Put close to 10K on one of those, although the thin O-rings used for a belt were somewhat fragile. At the time I had the good fortune of working at a place where a suitable replacement O-ring was available to me from lab stock.