Knowledge of end-to-end path capacity is useful for video/audio stream adaptation, rate control and overlay design. Capacity estimation in wired and last-hop wireless networks has been extensively investigated, but an in-depth study of path capacity in ad hoc, multihop wireless networks is still lacking. Since the "capacity" of a wireless link can vary dynamically and rapidly due to changes in interference, mobility or energy optimization policy, timely path capacity tracking is the key to efficient routing, traffic management and application deployment. In this paper, we present AdHoc Probe, a "packet-pair" based technique, to estimate end-to-end, path capacity in ad hoc wireless networks. Using analysis and simulation, we show that AdHoc Probe converges fast and thus works well in mobile, rapidly changing scenarios. AdHoc Probe is simpler, faster and less intrusive than previously proposed schemes.