A monitoring assembly for a pneumatic tire includes an electronic monitoring device having at least one sensor disposed in a protective body. The monitoring assembly may be configured to float on a variety of liquids that are typically disposed within a tire. The body includes a device that predictably orients the monitoring assembly when the assembly is floating in the liquid. The monitoring assembly is simply placed in a tire before the tire is mounted on a vehicle rim and allowed to move about loosely in the tire chamber when the tire is in use.