Grid architectures are execution environments that are known to be at the same time distributed, parallel, heterogeneous and dynamic. While current tools focus solutions for hiding distribution, parallelism and heterogeneity, this approach does not t well their dynamic aspect. Indeed, if applications are able to adapt themselves to environmental changes, they can benet from it to achieve better performance. This article presents Afpac, a model extending Dynaco for designing self-adaptable parallel components that can be assembled to build applications for Grid. This model includes the denition of a consistency criterion for the dynamic adaptation of SPMD components. We propose a solution to implement this criterion. It has been evalued using both synthetic and real codes to exhibit the behavior of several proposed strategies.