Lucien Juy

Lucien Charles Hippolyte Juy was a French industrialist who made derailleur gears.

Lucien Juy owned a bicycle shop in Dijon, Côte d'Or, France.

The whole arm was spring-loaded in order to tension the chain – this was the first use of the sprung top pivot which was to become an essential part of the modern indexed derailleur as we know it today.

[5] In 1962 Juy broke with tradition and made his front and rear derailleurs with nylon frames.

[6][7] A historian of bicycle derailleurs, Michael Sweatman, says: "He did not do things by halves - instead of dipping in a toe and using the odd plastic part - he jumped in up to his neck and made the entire parallelogram - both knuckles and both parallelogram plates - out of polyoxymethylene (which Du Pont branded as 'Delrin').