3:27 PM

Plastique

Back in the 70s and 80s the French company Simplex experimented with plastic components for bikes.  I’m too young to know how they worked when they were new and how they compared to conventional components of their era but the way I see them today: total junk.
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These components always came on French bikes such as Peugeots.  Maybe the designers didn’t plan on the bikes lasting 40 years, or maybe they did but failed horribly.
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The first thing you’ll always see is the broken shifter lever.  98% of the time they’re broken.  If they’re not, they will be. Maybe people were weaker and therefore more gentle back then.  In any case they wont work in today’s world so if you have a set i suggest changing them out.
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Front derailers were quite interesting.  The front clamp piece is an aluminum one while the rear main body of the derailer is plastic.  The main problem with this (with many other intrinsic design flaws)  is that the plastic isn't strong enough to hold the clamping force.  Once old or torqued too much, the threaded hole breaks. 
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The rear derailer doesn't have as much bad use of plastic parts but it isn't designed well either.  Shifting is usually far from smooth and the thing just looks bad.  Bikes like these are usually valued for their frames.  In the case of these old components, it makes them a good candidate for a cheap fixed gear/ single speed conversion:
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