Who is the current youngest? Merckx? Cav?
Dietrich Thurau was 23 years 6 months when he completed stage wins in all 3 grand tours. There was a thread about it in 2011
Youngest rider to win a stage in each gt?
I've always been curious, who was the youngest, and how old was he, when he won a stage in all 3 GTs, for the record I'm not talking about the youngest rider in each GT to win a stage, I mean the youngest to have a stage win from each GT. Thanks.

Sagan and Pogacar could have beaten the record since then but never attempted the Giro when they had the chance. Ewan could have done it at Tour 2017 but wasn't selected. Biniam will be 23 years 5 months and 8 days on the last day of Vuelta 2023.