• It's a "bi-chain" with two sprockets each side giving four gears or eight, I think there are two chainrings each side, - one of Velocio's own builds about 1909/10.

  • Ta! Is there an idler wheel you put the non-driving chain on or something? Can't find any decent photos/descriptions in a quick hunt online.

  • Only info I can find is from The Golden Age of Handbuilt Bicycles by Jan Heine and Jean-Pierre Praderes, beautifully illustrated with other early innovations as well.

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