The Super-Leader Compétition is characterised by an automatic regulator of chain tension - that's the long and elegantly curved spur that runs through the loop at the end of the sprung arm. Carefully regulating chain tension was a huge concern in the 1950s - and then was forgotten forever because... it doesn't really matter.

(Source gallica.bnf.fr/ Bibliothèque nationale de France)

• Publisher: L'Officiel A.C.M.
• Country: France
• Date: January 1951
• Derailleur brands: Super-Leader
• Derailleurs: Super-Leader Compétition