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Vintage Components - Simplex front derailleurs

Simplex front derailleurs on this page: SX A32 clamp-on | Simplex-Peugeot SJ A102 front 28.6mm clamp-on

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Simplex founder Lucien Juy owned a bike shop in Dijon, France, when he began making his first derailleurs in 1928. His innovative designs were a hit and by 1933, Juy said he was making 40,000 derailleurs a year.

It wasn't until 1961 that Simplex adopted the deforming parallelogram that Campagnolo had popularized with its ground-breaking Grand Sport derailleur a decade before. But Juy's Simplex derailleurs had a sprung top pivot, the way all derailleurs are made today. At the time, that Simplex Export 61 was probably the best-shifting changer made.

A year later Juy decided to make Simplex derailleurs out of an acetal resin (OK, plastic) made by Dupont called "Delrin". It was a terrible mistake. Juy took what was the best derailleur in the world and turned it into a flimsy, delicate changer.

In the early 1970s Juy again began producing superb changers when he came out with the alloy Super LJ series. They were nicely finished, well-designed, good shifting derailleurs.

No amount of innovation or quality improvement could stem the Asian onslaught, exacerbated by association with those delrin derailleurs that came on so many bike-boom bikes. Simplex ceased production in the 1990s.


Simplex SX A32 front 28.6mm clamp-on front derailleur. Used, $35.00/each

  • Produced in the mid-1980s
  • Delrin body, steel cage
  • Will handle up to a 14-tooth difference in front chainrings.

Simplex front derailleur

Side view

Simplex front derailleur

From the front.

Simplex front derailleur

From the back.

Simplex front derailleur

From behind


Simplex-Peugeot SJ A102 front 28.6mm clamp-on derailleur. Used, $35.00/each

  • As a Simplex branded derailleur it was produced from 1979 until 1989.
  • It was often used on high-end Peugeot bikes in the early 1980s.
  • This was also sold by Gipiemme as a "Sprint" front derailleur.

Simplex front derailleur

A simple, solid design that Simplex produced for a decade.

Simplex front derailleur

From the front

Simplex front derailleur

Back of the derailleur

Simplex-Peugeot front derailleur

From behind