A disparagingly named series of bike rides originating in Grosse Pointe covered nearly the entire city. Rides were based on major roadways: following Grand River, Outer Drive, etc. You can see the common entry roadway was along E. Jefferson Ave and routes are more dense Downtown where the rides would stop for food and drinks. The organizer, Arthur Miller, spent a good amount of time taking picture to document the various areas of Detroit. His photos have captured some excellent Detroit painted typography as well as massive pot holes.
Now there are a plethora of organized bike rides around the city: Critical Mass, Criterium, Tour de Troit, Slow Roll, Bike Detroit, Wheelhouse Detroit, etc.