The global transition towards sustainable mobility is accelerating, with electric vehicles (EVs) at the forefront of this paradigm shift. While much research focuses on the general population's adoption barriers, a critical and growing segment remains under-explored: existing electric bike (e-bike) users. This study assumes a "stepping stone" hypothesis, positing that the positive experience and technological familiarity gained from e-bike ownership significantly influence the preference for adopting electric cars (e-cars). The primary objective of this research was to identify and analyze the key determinants influencing an e-bike owner's intention to purchase an e-car. A quantitative research methodology was employed, utilizing a structured questionnaire distributed to a targeted sample of 285 current e-bike users. The research model integrated constructs from behavioral spillover theory and technology acceptance models, examining factors such as E-bike Satisfaction, Perceived Environmental Impact, Reduced Technology Anxiety, and Perceived Financial Benefit. Findings from multiple regression analysis reveal that Reduced Technology Anxiety, stemming from prior e-bike usage, is the most significant predictor of e-car purchase intention. Users comfortable with charging routines and battery management on a smaller scale are less intimidated by e-car operations. Furthermore, E-bike Satisfaction and Perceived Environmental Impact showed strong positive correlations with purchase intention. However, Perceived High Upfront Cost remains a significant barrier, even for this environmentally conscious segment, indicating that financial incentives are still crucial. The study concludes that e-bike users represent a "warm lead" segment for e-car manufacturers. The implications for industry suggest targeted marketing strategies that leverage their existing knowledge base—framing the e-car as a natural upgrade. For society and policymakers, promoting e-bike adoption could serve as an effective, lower-barrier entry point into the broader electric mobility ecosystem, eventually fostering higher e-car adoption rates.