The story of the Spanish derailleur is the story of two brands, and two social and economic factors.
The first of the two social and economic factors was Spain’s isolation during the years of Franco’s fascist dictatorship (1936 to Franco’s death in 1975 and on to 1978 and the adoption of a new constitution). Although Spain was open to tourists, and Spanish industry could (and did) trade with the world, Spain remained an insular society, both shunning and shunned by the outside world. The history of Zeus somehow reflects this, the company’s focus on self reliance, building both bikes and components, its deep sense of being wronged in some way by history and/or the world’s devotion to Campagnolo - both reflect the inward looking nature of Franco’s Spain. But this slightly paranoid world view also seems to have provided the energy that drove Zeus - once Spain emerged from its isolation to become a more ‘normal’ European country the company rapidly disappeared.
The second factor was the notion of Spain as a low cost version of Italy. It’s easy to forget that Spain in the 1960’s was a poor country with low wages - a natural location for FIAT to set up SEAT to manufacture its basic models, like Cinquecentos and Pandas. An equally natural place for Triplex to manufacture slightly nasty, cheap, knock-offs of Campagnolo Nuovo Record’s and sell them to French bicycle manufacturers. Again this was a business model that would not stand up to Spain’s emergence as European economic power brimming with style and confidence - and with the wages to match.