Nicknamed Il Leone del Mugello, "The Lion of Mugello" (from his birthplace Barberino del Mugello, near Florence), Nencini was a powerful all-round rider, but particularly strong in the mountains.
Nencini was born in Bilancino di Barberino, Tuscany. He was an amateur painter and a chain smoker. He was particular gifted as descender. "The only reason to follow Nencini downhill would be if you had a death wish", said the French rider Raphaël Géminiani.
