Not content to just copy the Japanese design, Campagnolo designed the Chorus with a special 2-position parallelogram that could be tilted a little or a lot, depending on the range of the freewheel being used. 1988, said, "We found Chorus worked better than any other Campy derailleur -- including the top-of-the-line C-Record.The Chorus derailleur shifted more precisely and was a lot quieter than past Campy derailleurs." They went on to say, "If you want indexed shifting on your all-Campy bike, Chorus plus Synchro is the best combination." As glowing as that review was, I don't believe that opinion was shared by all.
The 2-position parallelogram was a really interesting idea -- but it never caught on. In early 1988, Campagnolo released Croce d'Aune, named after the famous mountain pass where the young Tullio Campagnolo, his fingers frozen numb in the cold, was inspired to create the first quick release hub. Like the C-Record and almost all other Campy derailleurs dating back to the original Gran Sport, it utilized the traditional hanging parallelogram structure.
Unlike any other, it used a combination of cable actuation and an unusual articulating tie-rod to keep it tracking the cogs closely with a narrower chain gap. According to Chuck Schmidt, of Velo-Retro, the top of the tie-rod was held by the derailleur fixing bolt with a ball joint, and the bottom of the rod moved with the derailleur body.
Campagnolo took a very different approach than the Japanese to indexing with their Syncro design in 1987.
Whereas Shimano and Sun Tour designed full systems of interrelated parts -- shift levers, derailleurs, freewheels/cassettes, chains, and even cables (necessitating a complete drivetrain component upgrade, or better yet, just a whole new bike) -- Campagnolo, on the other hand, tried to make Syncro work with their existing derailleurs. The standard parallelogram with a single spring-loaded pivot (which essentially dated back to about 1950) did not track the cogs as closely as the dropped/slanted parallelogram architecture, had a wide "chain gap" on the smaller cogs, and required a fair amount of the overshift/back-off technique to make the shift.
One might think of our distant forebearers, the Neanderthals (Homo Neanderthalensis) -- not a direct ancestor exactly, but more like an evolutionary cousin, whom some anthropologists believe may have even co-existed with early Homo Sapiens, but eventually died off, becoming an evolutionary dead-end.
In looking at bicycle derailleurs over the past couple of articles (HERE, and HERE), I couldn't help but see a similar phenomenon -- evolutionary dead ends in the line of bicycle components.The complicated and unusual structure never caught on and it was redesigned a few short years later. In 1988-89, the Athena group was introduced, with yet another derailleur design.At first glance, the Athena appeared to share the traditional Campagnolo parallelogram structure. If one looks a little closer, it becomes apparent that the parallelogram is actually canted at an angle.Pulling the lever to shift, the cable pulled the body back, while the tie rod pushed the derailleur body inwards, driving it from one cog to the next.Again, the claim was that it would work better with indexed shifting -- but the market must have believed otherwise.None of this translated to good success with indexing.