The "Pedal for Parkinson's ride" was set to leave Navy Pier at 10:30 a.m.
The Chicago riders call themselves "Team Route 66". They include a dozen riders who are living with Parkinson's.
The group hope to arrive in Phoenix by May 24 for the World Parkinson Conference.
The conference welcomes neuroscientists, clinical researchers, clinicians, nutritionists, people with Parkinson's, care partners and others.