E-bikes are increasing popular. Their health and environment benefits depend strongly on the transport modes they replace. This paper addresses the multiple dimensions of the modal shift induced by e-bikes (motivations, uses, substitution, renunciation). It is based on biographical interviews (n = 24) and a survey (n = 1466) in Lausanne, Switzerland. Results show that e-bikes are used very frequently and for a variety of reasons (mostly utilitarian). They substitute all modes (mainly public transport, walking and the car but also cycling) and may lead to giving up regional transport passes, motorized two-wheelers and cars. E-bikes are also a way to continue cycling (despite age, children, physical condition) and to avoid switching to motorized modes. The paper calls for approaching modal shift through three perspectives to understand how e-bikes (1) fit in the transport system (systemic approach), (2) within individuals’ mobility biographies (life-course approach) and (3) within the everyday organization of individuals and households (lifestyle approach). It finally argues that e-bikes should be at the core of planning – along with other forms of active mobilities and public transport – as they are a readily available way to foster decarbonization of transport.