| 摘要 |
A pneumatic tyre comprising a tread part (T) having two circumferential grooves (7) continuously extending in the circumferential direction on either side of the tyre's equator (CL) so as to divide the tread part (T) into a pair of shoulder parts (8), which are located outside outer bottom edges (7b) of the circumferential grooves (7) in the axial direction of tyre, and a central part (9), which is located between inner bottom edges (7a) of the circumferential grooves (7) in the axial direction of tyre, characterised in that the central part (9) has a surface comprising successive convex curves composed of a pair of inner groove walls (9A) extending inwards, in the axial direction of tyre, along a curve convex outwardly in the radial direction from the inner bottom edges (7a) of the circumferential grooves (7) and a central ground-contacting surface (9B) smoothly connected between the pair of the inner groove walls (9A), the central ground-contacting surface (9) is substantially in contact with a virtual tread line (10) between outer surfaces (12) of the shoulder parts, and when the tyre is mounted on a regular rim, inflated to its regular internal pressure and has applied its normal load, a ground-contacting area Fc where the central part (9) contacts the ground has a length Lc in the tyre's circumferential direction which is 0.9 to 1.1 times a length Ls in the tyre's circumferential direction of a ground-contacting area FS where the shoulder part contacts the ground. <IMAGE> |
