The early Shimano 600 derailleurs were revolutionary in a number of ways. They were part of a full groupset - a new phenomenon for a mid level price point, they were designed for Campagnolo drop-outs (gone was the homage to Simplex), and most important of all, they were well finished and looked ruthlessly composed and modern. I can well remember marvelling at the sheer glamour of mid-range bikes kitted out in the full 600 groupset - they looked so much better than their peers clad in a mishmash of Weinmann centre pulls, SR cranks and SunTour V series gears.
This example is a long pulley cage version of the very first generation which, I have been told, have 6000 model numbers (which makes sense - but I have never seen these numbers in a catalogue). The distinguishing feature is that the ‘600’ on the outer parallelogram plate is in large script.
All in all, a pretty damn fine derailleur - even if it did not change quite as well over a wide ratio freewheel as a SunTour Vx GT.
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