The ideological fit between party grassroots and leaderships has long been a concern for political science,with members in general, and young members in particular, thought to be more radical. However, we do not know,first, whether this is still the case and, if it is, what drives members in different ideological directions. To investigate,we propose a new typology of members as radicals, moderates and aligned, and develop a theoretical frameworkthat accounts for how political socialization and party contexts drive congruence and incongruence. We test thisusing YOUMEM survey data from over 4,000 members of 12 youth wings in six countries. Our results show thatwhile radicals are the largest group in most youth wings, they are more common on the centre-left than the centre-right. They tend to have been in the youth wing for longer than aligned members, but are under-represented amongpolitically ambitious members. Our findings thus shed light on opinion structures within political parties and providea typology for future research on intra-party cohesion.