The instant invention is a pressure release safety system for a multi-piece wheel rim and tubeless tire combination, teaching designs for automatically relieving/releasing pressure as part of its disassembly. In this invention, fastening elements used to hold together portions of a wheel rim are provided with a blocking device or devices that prevents loosening and/or removal of fastening elements until said blocking device is first moved from a blocking position, where movement of the blocking device from its blocking position directly or indirectly opens or requires the opening of a pressure relief channel or channels—allowing, enabling and effecting depressurization of the sealed pressure vessel. When applied in the context of a tubeless two-piece wheel/tire assembly, the invention advantageously may include a blocking or safety device (typically in the form of a ring) that covers all or a critical portion of the nuts/studs that hold the two piece wheel together. The act of removing the safety ring so as to access and remove the nuts from the studs to disassemble the wheel, opens an air channel in communication with the tire interior so as to allow pressure to escape from the tire interior.