Politecnico di Torino - Corso Duca degli Abruzzi, 24 - 10129 Torino, ITALY

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Electronic shifting cassette gearbox with linear drive inside the shaft

BicycleBike gearsElectric drivesGearboxIntegrated system


The system implements a gearbox for chain transmissions by translating the sprocket set from inside the same shaft on which it is housed. It totally eliminates any external encumbrance of the actuation system (apart from the electric control cable) allowing complete integration which makes it suitable for application on traditional bicycles.

Technical features

The projects and prototypes of shifting cassette cycling gearboxes have all the handling carried out from the outside and therefore require special support portals and mechanical connections that are poorly integrated in some contexts, such as on conventional cycling frames. The invention overcomes this limit, allowing the cassette to be controlled and moved through a servomotor housed inside the same splined shaft, offering an aesthetically very clean solution that can be integrated into a wide variety of contexts (starting with cycling frames). The solution identified therefore eliminates the need for external modifications to the frame except for specific design choices, such as the widening of the wagon (in the case of the bicycle) to increase the number of sprockets that can be housed, a choice that the system makes possible by overcoming the limit imposed by the misalignment. of traditional exchange rates.

Possible Applications

  • Traditional and pedal-assisted cycling;
  • Human-powered vehicles;
  • Contexts that require motion transmission with multiple speeds.


  • Miniaturized and integrated system;
  • Less weight and greater versatility than traditional solutions.