This article argues that in order to analyse democracy as a pattern constantly processed in a given society, it is useful to look at activist groups' agenda setting and recruitment principles, group bonds and boundaries, and how these actions direct and influence ways of creating the common. Based on an ethnographic study on bicycle activism in Helsinki, Finland, it describes a local critical mass movement that was successful in promoting a bicycle friendly and sustainable city, yet dissolved due to lack of people involved, and the bicycle demonstrations stopped at a moment of high public interest. This empirical puzzle is addressed by combining three theoretical perspectives: Kathleen Blee's work on path dependencies in nascent activist groups; Nina Eliasoph and Paul Lichterman's work on group styles, and Laurent Thevenot's work on the grammars of commonality. These theoretical tools help understand the sense of what is deemed possible, desirable and feasible in activist groups, and the consequences thereof to social movement 'success' and 'failure'. The article claims that everyday practices and interaction are crucial in understanding the 'democratic effects' of social movements. It concludes that following specific processes of politicization and their conditionings in activist groups provides keys to understanding contextual differences in democracies without resorting to methodological nationalism or to exaggerated global isomorphism, and thus may contribute to figuring out how to succeed global action plans over wicked, pressing problems like global warming.