First book of a very good series of Christian fiction books for kids, allegory on spiritual warfare. I think they get better as the series goes on, but this one is important to read first... starts the story going.
From the back cover: "When John Kramar comes across an old, rusty Spirit Flyer bicycle, he finds it is far from ordinary. First, the bike helps him save a neighbor's barn from burning. Then it brings him into conflict with the boys in the Cobra Club, a representative of Goliath Toys and other forces that not only want John's bike, but want it destroyed."