This study examines the ethics and politics of knowledge across 15 distinctive community-engaged research projects. We focus our analysis on interviews with community partners and consider their perceptions of research, academic research partners, motivations for partnering, and the benefits and challenges of community-engaged research. We highlight three themes: Community partners' (1) motivations to know better and more systematically what they already know, (2) interests in legitimating community-based knowledge (i.e., knowledge produced beyond the academy), and (3) efforts to navigate often inflexible university timelines and budgetary processes. Our findings highlight concerns at various ethical, political, and epistemic intersections and connect to the possibilities and limits of equity-oriented collaborative research methodologies for redressing epistemic and social injustices. We suggest that these challenges need systematized attention if the field of community-engaged research is to achieve the epistemological and social justice missions that are often articulated as the aspirations of such partnerships.