1930s: Technical Trials
René Herse entered the bicycle world with a splash at the 1938 Technical Trials. He rode for Narcisse, but his bike was equipped with Herse’s own components. This amazing bike weighed just
7.94 kg (17.5 lb), fully equipped with fenders, lights, racks and wide tires. The Technical Trials were epic events with the goal was to find the best bicycle. Points were awarded for light weight and desirable features. After the initial judging, the bikes had to prove themselves over hundreds of kilometers of rough mountain roads. Any defect incurred penalties. The bike with the most points won.
In 1938, René Herse’s bike came second – his Stronglight bottom bracket had developed play. From then on, Herse’s bikes always placed first or second in the Technical Trials. These challenging tests advanced bicycle design like no other event. Builders pioneered aluminum cranks, cartridge bearings in hubs and bottom brackets, cantilever brakes, and low-rider racks. The Trials showed that bicycles could combine light weight and performance with excellent reliability.
https://www.compasscycle.com/rene-herse/
Damals gab es übrigens noch kein 531 SL oder 531 Legere. Somit sind 8,6 kg ohne Schutzbleche, Träger etc. durchaus drin.