Gino Bartali rode his bicycle up and down the mountains of his homeland. His training rides were long—miles and miles and miles. With his bravery and his bicycle, he would save many lives during World War II.

Mr. Bartali was born in a small Italian village in 1914. As a teenager, he worked in a bike shop. When not at work, he rode his bike for hours. Soon he became a champion cyclist. Mr. Bartali went on to win many important titles. But his life was more than bikes. His long rides hid a top-secret activity: saving Jews.

No one was surprised to see the famous Gino Bartali cycling around the Italian countryside. He often wore his racing jersey. His name was printed in large letters on the back. No one—not Nazi patrols or Italian police—wanted to interrupt Mr. Bartali’s training.

But in his bike frame, Mr. Bartali hid papers and photos. The documents were fake permits. These would help Jews hide their identities. He carted them back and forth from a secret printing press. He delivered them far and wide.

One time, Mr. Bartali pulled a wagon behind his bike. Inside were Jewish refugees. Up, up the steep Swiss Alps he cycled. He must have had very strong legs and lungs! Along the way, he met many patrols. He told the officers the heavy wagon was part of his intense training.

The police stopped him another time. They searched him. Mr. Bartali asked one favor. He asked them not to touch his bicycle—because it was very fine-tuned.

Mr. Bartali didn’t talk about how he used his bicycle for good. After his death in 2000, his son began to tell his father’s story. Mr. Bartali didn’t think of himself as a hero. He said simply, “Real heroes are others; those who have suffered. . . . I’m just a cyclist.”