We introduce a new class of ventilated brake disk which incorporates an open cellular core: wire-woven bulk diamond (WBD). Transient and steady-state thermofluidic characteristics are presented. As reference, a commercially available pin-finned brake disk is also considered. At a braking power of 1.9 kW, representative of a medium sized truck descending a 2% gradient at a vehicle speed of 40 km/h (i.e., 200 rpm), the WBD cored brake disk reduces the overall brake disk temperature by up to 24% compared to the pin-finned brake disk. Results also reveal that in typical operating ranges (up to 1000 rpm), the WBD core provides up to 36% higher steady-state overall cooling capacity over that obtainable by the pin-finned core. In addition, the three-dimensional morphology of the WBD core gives rise to a tangentially and radially more uniform temperature distribution. Although the WBD core causes a higher pressure drop, this is balanced by the benefit of a stronger suction of cooling flow. Flow mixing in an enlarged heat transfer area by the WBD core is responsible for the substantial heat transfer enhancement. The WBD core is mechanically strong yet light while providing a substantial reduction in a brake's operating temperature.