This, rather rudimentary, twin pulley derailleur was initally marketed as ‘Le Lautaret’ (named after a pass in the Alps that has now been on the route of the Tour de France on 40 occasions).
According to Frank Berto, Francis Charvin then changed his mind and renamed it the GRI-GRI Route. Frank Berto goes on to suggest that, at some point this derailleur was re-renamed ‘Le Lautaret’. Francis may not have been an unnecessarily decisive man.
I believe that this derailleur was shown at ‘La cinquième semaine du cycle de Saint-Étienne’ in November 1931.
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