Written by Paul de Vivie, this is the second of two articles considering ‘the future of the mixed tandem’. I think that the French word ‘mixte’ here does not refer to the idea that the tandem is suitable for both men and women, but, instead, refers to the idea that it has a multi-use transmission with different gear ratios.
The article contains much discussion of (and admiration for) the Whippet both as a specific product and as a general term for derailleurs. As far as I can understand it, Paul de Vivie lists the two disadvantages of derailleur systems as being, firstly, that changing gear requires considerable skill particularly to find the exact point where the chain is properly aligned with the desired cog and, secondly, that the gear change is less than instant. Anyone who is old enough to have ridden bicycles in those dim, dark, dreary, dank days before Shimano’s SIS will understand exactly what he is going on about. Given Paul de Vivie’s nationality (and evident patriotic pride), it would be rude to point out that, as late as the 1980s, French derailleurs proudly running French chains over determinedly French freewheels were particularly prone to these twin disadvantages.
(Source gallica.bnf.fr/ Bibliothèque nationale de France)