Analysis of information sources in references of the Wikipedia article "Yellow jersey statistics" in English language version.
Frantz, André Leducq and Victor Fontan, who were in that winning stage 17 break, were exactly tied in time. Today the judges would go back to the time trial and look at the fractions-of-a-second differences. If that doesn't resolve the tie, then a look at placings solves the problem. The Tour didn't have rules to take care of ties, so 3 Yellow Jerseys were awarded.
Leading up to the Pyrenees, Italy's ace sprinter Rafaelo di Paco dueled with France's Charles Pélissier for stage wins and the lead. After stage 5 they shared the lead for a single day.
