Stronglight is based in Saint Etienne, traditionally a centre of the French cycle component industry.

I think the Stronglight story goes something like this:

• The Stronglight brand was introduced in 1933 by a company called Verrot Perrin which primarily manufactured chainsets.
• The iconic Stronglight 49D chainset was introduced in 1949.
• In the 1970’s Verrot Perrin was taken over by Haubtmann (Solida), another venerable French chainset manufacturer.
• In 1993 the company went bankrupt and was bought out by some of its employees.
• Then in 1999 the company was bought by IRCOS, a management buy-out from SRAM of some of Sachs’s French factories, including the old Huret factories in Chepy.
• In 2001 IRCOS went bankrupt and Stronglight was bought by the Zefal group - which owned it until 2009.
• Finally, in 2009, a M. Glotin, the Managing Director of Zefal, left Zefal and bought Stronglight - and owns it to this day.

I think the Stronglight derailleurs date from the IRCOS period and were launched in late 2000 for model year 2001. IRCOS had all the factories needed to put together a groupset, and used the Stronglight brand, as this was the only brand name that it owned (all the other brands were owned by SRAM). It’s derailleurs were Sachs designs. I believe that the derailleur range included 6 models:

For road bikes...

• Stronglight Speedlight based on the Sachs New Success
• Stronglight Mygal possibly based on the Sachs Rival 7000
• Stronglight Asphalt possibly based on the Sachs 3000 or 5000

For mountain bikes...

• Stronglight Century based on the fibre-reinforced-composite Sachs Plasma
• Stronglight Rockstrong based on the long cage Sachs Quarz
• Stronglight Rockstrong DH Trial based on the short cage Sachs Quarz

I believe that the model in this collection was a prototype version of the Rockstrong that never went into production in those, very particular, colours.

After Zefal took over, the Stronglight brand was (wisely) only used for chainsets and headsets.

My thanks go to Bruno Déreux for his invaluable information.