I wonder just how prevalant Schrader valve bike tubes were outside the US? I think stumbling block to non presta was lack of decent frame pumps that could inflate tires to higher pressures. Touring with Schraders created issues with gas station compressors only putting out low pressure and basic frame pumps being just that. Zefal HP was really the first frame pump in general distribution that had a Schrader version. There might have been French ''express valves'' that would screw into your Zefal pump prior to this (AFA?) to allow Schrader usage. We redrilled many rims from Schrader to Presta (adding a Presta hole at 90o as I recall)
BOB FREITAS
MILL VALLEY, CA USA