| 摘要 |
A pneumatic radial tire for a motorcycle comprising a belt (24) containing cords (24a) extending substantially in a circumferential direction of a tread and having a directional tread pattern defined by main slant grooves (11,12) each having an acute-side inclination angle ( beta ) of not less than 45 DEG with respect to the circumferential direction of the tread and extending from a tread center (C) or a vicinity thereof up to a tread shoulder region, and a slant sub-groove (13;14;15;16;17;18;19;20) extending between the slant main grooves (11,12) and having an acute-side inclination angle (&thetas;) with respect to the circumferential direction of the tread less than that of the slant main groove; wherein a groove width of the slant main groove (11,12) is within a range of 3-15% of a peripheral length between both ends of the tread when the tire is mounted onto a standard rim and inflated with an air pressure corresponding to 80% of a maximum air pressure with no loading; wherein a main portion of the slant sub-groove is terminated so as not to open into the slant main groove; and wherein the main portion of the slant-groove has an acute-side inclination angle &thetas; of 0-30 DEG with respect to the circumferential direction of the tread, a groove width narrower than that of the slant main groove, a length in the circumferential direction of the tread corresponding to 30-80% of an arranging pitch of the slant main groove, and a depth corresponding to 50-100% of a depth of the slant main groove. <IMAGE> |
