This 12-month ethnographic study of an early entrant into the U.S. car-sharing industry demonstrates that when an organization shifts its focus from developing radical new technology to incrementally improving this technology, the shift may spark an internal power struggle between the dominant engineering group and a challenger occupational group such as the marketing group. Analyzing 42 projects in two time periods that required collaboration between engineering and marketing during such a shift, we show how cross-occupational collaboration under these conditions can be facilitated by a radical flank threat, through which the bargaining power of moderates is strengthened by the presence of a more-radical group. In the face of a strong threat by radical members of a challenger occupational group, moderate members of the dominant engineering group may change their perceptions of their power to resist challengers' demands and begin to distinguish between the goals of radical versus moremoderate challengers. To maintain as much power as possible and prevent the more-dramatic change in engineering occupational goals demanded by radical challengers, moderate engineers may build a coalition with moderate challengers and collaborate for incremental technology development.Keywords: cross-occupational collaboration, coordination, adaptation and inertia in technology-based organizations, radical flank effect, power, conflict, intraorganizational power struggles Most technology-based organizations must at some point shift their focus from developing radical new technology to incrementally improving this technology over time, but the literature has not explored the challenges associated with 1 MIT Sloan School of Management this common transition or elaborated the mechanisms that facilitate it. Most research on technology development during organizational transitions has focused on how firms develop-or fail to develop-radical new technologies (e.g., Christensen and Bower, 1996;Tushman and O'Reilly, 1996;Tripsas and Gavetti, 2000). It assumes that the shift from a period of radical innovation to a period of more stable, incremental innovation, which happens in both incumbent firms and new entrants, is relatively straightforward. From a capability perspective, once a new technological trajectory has been identified, a firm's move from radical to incremental innovation should be relatively easy. Yet modifying an organization's initial innovative technology shifts the balance of power away from the engineering group, which may have long been dominant, toward challenger groups, such as the marketing group, that are better able to contribute to new demands, like satisfying the needs of mainstream customers (e.g., Burgelman, 1994;Christensen and Bower, 1996). In the midst of the power struggle that is likely to emerge between the dominant and the challenger occupational groups in such situations, the challenger group must persuade members of the dominant group to collaborate to accomplish incremental technology development...