The disruptive rise of the sharing economy has inspired multiple social innovations embodying significant potential towards achieving urban sustainability in crucial areas like low-carbon mobility. Increasingly, consumers in such sharing systems participate in activities of value co-creation together with firms and peers, such as through enforcing rules that help maintain trust and reciprocity. Why do people choose to invest their time and energy in co-creating values that may benefit wider social and environmental sustainability in the sharing economy? This study addresses this question through an analysis of an emerging shared mobility community, the innovative socio-economic relationships it has spawned, and the cultural and cognitive forces that underpin these new forms of economic organization and value creation in relation to sustainability. Through a mixed method case study of a newly emerged free-floating bike sharing system in China, called Mobike, the paper explores the main enabling factors which is transforming people from passive product/service receivers to active value co-creators in the sharing economy, such as self-efficacy, cognition of duty, anticipated awards and learning processes. The paper argues that business, social and government organizations may leverage these enabling factors to achieve a more sustainable sharing business and society. Finally, based on quantitative and qualitative data analysis, the article proposes a value co-creation framework between users and firms that involves a clear social learning process on the one hand, and has strong links with social innovations towards sustainability, on the other.