© 2016 IEEE. Bicycle theft is a big problem in places such as university towns, where bicycles offer one of the most costefficient and quick ways for students to move around. For example, 1,200 bicycles are stolen yearly in Göttingen, with more than 300,000 being reported as stolen in the whole of Germany during 2014. We present a power efficient architecture to track the locations of stolen bicycles using opportunistic communication with collection nodes placed in high traffic spots, that can be used to find stolen and lost bicycles. At the same time, the scheme is designed to prevent a loss of privacy for the owners of bicycles that have not been marked as stolen, while also reducing power usage during times where bicycles are under the control of their proper owners.We also show the feasibility of our approach using a simplified implementation using IRIS nodes, with a university campus serving as a testbed.