Apparatus for inflating tires to a test pressure. The apparatus includes a shop supply of air and a regulated supply of air. A valve system is used to connect the tire to the shop supply to seat the bead on the test rim; to exhaust the air from the tire to bring the pressure in the tire to approximately the test pressure; and to the regulated supply to bring the air in the tire to the preselected test level. The difference between the actual test pressure and the desired test pressure is measured and that difference is used to control the pressure regulator so as to correct the test pressure in the next succeeding tire.