The Boneshaker by Kate Milford

This is an unusual book--you need to jump on, hang in there and trust the author, just as Natalie Minks has to do the same and trust herself to learn to ride the "boneshaker", an unusual, old-fashioned bicycle. When a strange, sinister travelling carnival comes to town, selling cure-alls to the townspeople, Natalie must thwart the Devil himself to save her town.