A tire inspecting apparatus for a tire is provided. The apparatus includes a test stand for supporting and rotating a tire. The test stand is configured such that a tire supported thereon defines a center axis. The apparatus includes a testing probe configured as a high voltage electrode for generating an electric field and a grounding element. A positioning assembly includes a support bracket and a positioning arm supporting the testing probe. The positioning arm is operable to move the testing probe into a working position between the sidewalls of a tire supported on the test stand and in proximity to the grounding element. The positioning arm is connected to the support bracket for pivoting movement relative to the support bracket about a pivot axis. The pivot axis extends at a non-perpendicular angle relative to the center axis of a tire supported on the test stand.