Flann O'Brien's stories always feature bicycles as the unavoidable props in his stereotypical Irish landscapes. In his novel The Third Policeman, bicycles are comically upgraded to full-blown characters and provide a recurring theme, lending linear consistency to an otherwise convoluted narrative. In Ireland, the (very real) national interest in bikes originally derives from necessity more than sports; in O'Brien's caricature, it becomes an obsession, and the bicyclist's relationship with his machine an improbable love-story. Bicycles betray the modesty of life in rural Ireland as much as they are a source of pride and joy when they display their owners' skills as mechanics or sportsmen. The aim of my paper will be to analyse the role of bicycles in the novel, both as symbolic attributes of the Irish common man and as structural devices in the narrative. O'Brien makes fun of the national vehicle and its users, playfully reminding us that cycling round and round is an ambiguous achievement. As a man-made device, the bicycle is also a direct application of mechanical science; thus the relationship between man and his machine comically reflects the mystery of creation, in a parody of the Great Clockmaker. The wandering bicycle finally represents the narrative structure of O'Brien's novel and his digressive representation of story-telling and language.