Our bodies experience a wide variety of kinesthetic forces as we go about our daily lives, including the weight of held objects, contact with surfaces, gravitational loads, and acceleration and centripetal forces while driving, to name just a few. These forces are crucial to realism, yet simply cannot be rendered with today’s consumer haptic suits, which primarily rely on arrays of vibration actuators built into vests. Rigid exoskeletons have more kinesthetic capability to apply forces directly to users’ joints, but are generally cumbersome to wear and cost many thousands of dollars. In this work, we present Kinethreads: a new full-body haptic exosuit design built around string-based motor-pulley mechanisms, which keeps our suit lightweight (<5kg), soft and flexible, quick-to-wear (<30 seconds), comparatively low-cost (~$400), and yet capable of rendering expressive, distributed, and forceful (up to 120N) effects. We detail our system design, implementation, and results from a multi-part performance evaluation and user study.Vivian Shen and Chris Harrison. 2025. Kinethreads: Soft Full-Body Haptic Exosuit using Low-Cost Motor-Pulley Mechanisms. In Proceedings of the 38th Annual ACM Symposium on User Interface Software and Technology (UIST '25). Association for Computing Machinery, New York, NY, USA, Article 1, 1–16. https://doi.org/10.1145/3746059.3747755