This is the second of three patents that, I believe, lead up to the design of the 1950 Selectic derailleur. This derailleur was a 3-speed device with no lever or cable - you operate the derailleur by back-pedalling.

This patent describes a twin pulley derailleur that is conceptually similar to the Selectic, but differs in small details. This patent is credited to Ange-Henri Le Beguec, from Rennes in France. Daniel Rebour describes this derailleur in the July 1946 edition of Le Cycle as being a 'Renalb-Lux'. You could, just about, think that 'Ren' referred to Rennes and 'alb-Lux' referred to some kind of alpine gearing of a luxurious nature. But the truth is that I can find no other useful references to Monsieur Le Beguec or Renalb-Lux.

• Publisher: L’Institut national de la propriété industrielle
• Inventor: Ange-Henri Le Beguec
• Country: France
• Date: Priority date February 1946
• Derailleur brands: Selectic
• Derailleurs: an early version of the Selectic