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Game changer: Campagnolo Gran Sport derailleur
Fanatics still fiercely debate who invented the derailleur, but the primary contenders for the title are Jean Loubeyre of France and the UK’s Edmund Hodgkinson, in the late 19th century.
Pioneering though both designs were, they were simple constructions that bore little relation to the intricate complexity of the modern derailleur. It took another 50 years and the creation of the Campagnolo Gran Sport to lay the foundations of what we still use today.
‘Simplex derailleurs dominated until 1951,’ says Mike Sweatman, owner of the world’s largest known private collection of derailleurs. ‘The Simplex is the pull-chain action, essentially a cable pulling the derailleur in and out against a spring. Then Campy’s Gran Sport introduced the parallelogram action.’
The Gran Sport, in principle, offered a far less crude mechanism for shifting across the rear sprockets, where the entire body of the derailleur twisted rather than simply pulling the jockey wheel into position with cable perpendicular to the cassette.
Campagnolo, then, lays claim to being the innovator of modern shifting. But, in truth, it wasn’t strictly the first. The little-known Nivex system actually beat Campy to the mark by a decade, with a parallelogram derailleur in 1938. The Nivex, however, attached to the bike via a clamp on the chainstay, rather than screwing into the hanger as the Gran Sport did, and it met with little commercial success.
Campagnolo’s experimentation with the parallelogram was a risk. The impetus came in 1949 after Fausto Coppi won both the Tour de France and Giro d’Italia using a Simplex derailleur, and Italian consumer attention was turned on the French componentry company that made them.
Legend has it that Tullio Campagnolo looked to create a racer-friendly version of the Nivex, which encountered problems with wheel changes across different frames. By mounting the system on the hanger, Campagnolo shifted the angle of the derailleur by 90° so it was now able to move out of the wheel’s path and allow the wheel to drop out, as is the case today.
The Gran Sport also boasted the first limit screws to restrict the movement of the derailleur beyond the scope of the cassette. The two-cable system used in the prototype meant the derailleur had to be pulled into a higher or lower gear, whereas the final version of the Gran Sport used a return spring to push the derailleur against the tension of the cable. All in all, the system worked faster and more accurately than derailleurs of the age, and was a success both commercially and in pro racing.
It wasn’t until 1964, when Japanese component giant SunTour developed the slant parallelogram, that the derailleur took on its modern form. SunTour’s derailleur offered a design that tracked the incline of the cassette, moving both vertically and horizontally.
That remains a design that every manufacturer now follows. Ultimately, though, the Gran Sport was a true departure from the derailleurs of its age, and everything that’s followed has been a refinement of that original design.
This article was first published in 2016.
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