The Derailleurs


Back in 1978 you had a good choice of Simplex rear derailleurs, but here we see two of them from that year in very different conditions. The better derailleur, as one would expect, has survived the years of service much better than its cheaper version. This is a Simplex rear derailleur test of the SX 410 and S001.



The Super LJ was the jewel in the Simplex derailleur catalogue, but the SX 410 in this video, which does look very similar to it, was an excellent derailleur and a good alternative to the SLJ 5500. On the other hand, the silver and delrin plastic S001 derailleur ( which is broken in the video ), sometimes known as the Prestige 2, was a much cheaper alternative and a standard component found on many lower to mid-range bikes in the late 1970’s. Just what the real differences are in shifting between iconic Super LJ and the SX 410 in this video is debatable, perhaps there are virtually none. However, what I can say is that I’ve come across quite a few cheaper Simplex and Huret derailleurs of this era that have suffered this same fate of losing their spring tension.


A Simplex S001


Spring Tension


The two derailleurs are about the same year; the better quality one still functions well, but the cheaper S001 no longer has spring tension. It is therefore easy to conclude that the cheaper derailleur hasn’t lasted as long, and the quality of the better made SX 410 is proved in its present swift and easy shifting. Just comparing their build quality tells a lot of the story: the S001 has delrin knuckles, cheaper metal, feels less solid.¬†Nevertheless, it’s impossible to know how both have been treated over the years, to know which one has had the harder life, the greater abuse. Both looked in the same cosmetic condition when I bought them, but the loss of spring tension is a major factor in the death of an old derailleur. The LJ lookalike will work for years longer.


The Prestige




The Prestige above I recently sold had great spring tension, so some are worth buying or keeping for your vintage bike. They will always have the reputation of being flawed. In the end it probably comes down to luck if you decide to buy an old Prestige; like buying a French car and hoping for the best.

  • Authentic Simplex Super LJ weight: from 189 to 230 grams
  • The Simplex Sx 410 in the video weight: 272 grams
  • The Simplex S001 weight: 226 grams
  • The Simplex Prestige ( above ) weight; 230 grams


  • Simplex Super LJ and SX 410 max cog: 30 teeth
  • Simplex S001 max cog: 30 teeth
  • Simplex Prestige AR 637 max cog: 34 teeth





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