The Shimano Sky Lark was Shimano’s take on the 1961 Simplex Juy Export 61. The Skylark has two sprung pivots, it is steel with no structural plastic parts, it has the pivot of the pulley cage offset from the axis of the pulleys and it works very well. Shimano called this combination of attributes their ‘Servo-Pantagraph’ design, and, despite this, it sold so well that they never looked back.
I think this example is the very first version with with the painted brass nameplate (love that red), the screw stop at the pulley cage pivot and the old style cable outer stop adjuster.
Shimano’s campaign of world domination began with this very model of derailleur.
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