methods and apparatus are provided for detecting when a spare wheel is used to replace a previously rolling wheel on a vehicle , where each wheel can transmit wheel id and motion status signals . the apparatus comprises a receiver , a memory for storing information relating wheel id and location , a processor coupled to the receiver and memory for analyzing the wheel signals to determine if the sp is rolling , and a timer coupled to the processor that measures how long the sp has been rolling . when the sp has been rolling for predetermined time t , the processor looks at the motion status signals from remaining wheels to determine which is stopped , and then modifies the information stored in the memory to associate the sp id with the wheel location formerly occupied by the now stopped wheel and associate the stopped - wheel id with the storage location for the spare .