Japanese Patent # S58-67586 - SunTour

Japanese Patent S58-067586  - SunTour main image

This SunTour patent from 1981 describes a parallelogram-free derailleur design that uses cog wheels to keep the pulley cage aligned to the chainline. SunTour never used this system on a production model - but 30 years later it was replicated in surprising detail in the FSA K-Force WE.

Browse associated derailleurs.

FSA K-Force WE thumbnail