PURPOSE: To prevent the worsening of high speed uniformity, by scraping rubber off the inner surface of a tire at a position of imbalance which exist in a tire unit.

CONSTITUTION: When there is imbalance at a position A of a tire, a radial run out increases at the position A with a higher speed because of a centrifugal force due to the imbalance to enhance radial force variation and tangential force variation in the high-speed uniformity. Rubber is removed from the rear of tread at the position A, namely, the inner surface of the tire to nulify the imbalance. This cancels a balanced force working on the entire tread even when the tire rotates at a high speed to check increase in the radial run-out even in a high speed operation thereby preventing the worsening of the high speed uniformity.