| 摘要 |
PROBLEM TO BE SOLVED: To provide a pneumatic radial tire having superior wandering resistance in driving on a recessed parts-formed road, including a track. SOLUTION: A pneumatic radial tire has a stepped-down part grounded on a central region including a tire equator surface and having a grounding width Wc of 30% under the grounded state of a tread part in which the tire filled with air pressure corresponding to maximum load capability is vertically pressed against a slab with a loading load equivalent to a maximum load capability of 70%. The pneumatic radial tire is provided with a tire having a ratio of the width A of the stepped-down part to the grounding width Wc, A/Wc, of 0.05 or above and a narrow groove extended in the rotatable shaft direction at the central region. The ratio of width B between both the ends of the narrow groove to the grounding width Wc, B/Wc, is 0.05 or above. |
