Pirelli

A car tyre (1), in particular a high or ultra high performance car tyre also suitable for use on track, is described. The tread band (8) of the tyre has a central region (L1) having a limited extension, separated from two large shoulder regions, respectively an outer shoulder region (L2) and inner shoulder region (L3). At least the outer shoulder region (L2) and the central region (L1) have a set, limited in type, number, size and extension, of transverse grooves. In the tread band (8) there are also annular portions (S1, S2, M) substantially lacking grooves.

A tyre for vehicle wheels comprises a tread band including a plurality of blocks and grooves that define in the tread band a void/solid ratio comprised between 0.4 and 0.65 and that form a tread pattern which is symmetrical with respect to an equatorial plane (X-X) of the tyre. The tread pattern includes a pair of circumferential grooves (20) arranged on opposite sides with respect to the equatorial plane and which define in the tread band a central annular portion and a pair of lateral annular portions arranged on opposite sides with respect to said central annular portion. The central annular portion comprises a plurality of circumferentially consecutive central blocks (30, 60) arranged astride of the equatorial plane and having a maximum width equal to, or greater than, 50% of a radial section maximum width of the tyre. The central blocks are separated from one another by a respective central transversal groove (45, 50) having a circumferential length less than that of a circumferentially adjacent central block (30, 60). Each central block comprises opposite axially outer faces (35, 65) inclined with respect to the equatorial plane by a predetermined angle and opposite circumferentially outer faces (32, 62) having an axially central portion (32a, 62a) perpendicular to the equatorial plane and opposite axially outer portions (32b, 62b) inclined with respect to a plane orthogonal to the equatorial plane by a predetermined angle different from 90°. Each lateral annular portion comprises a plurality of circumferentially consecutive lateral blocks (80, 90) separated from one another by a respective lateral transversal groove (85, 95). Each lateral block comprises an axially inner face (83, 93) having at least one part inclined with respect to the equatorial plane. At least one inclined part (83a, 83b) of at least some of the lateral blocks (80) is substantially parallel to at least one of said axially outer faces (35, 65) of said central block (30, 60).

A testing apparatus (10) for estimating parameters correlated to the interaction between a tyre and a surface. The testing apparatus (10) comprises an annular drum (20) rotatable about a drum rotation axis (X) and having a radially inner surface (21), a first driving device (30) configured to drive in rotation the annular drum (20) about the drum rotation axis (X), a tyre test sample (100) arranged on said radially inner surface (21) and a second driving device (40) configured to drive in rotation the tyre test sample (100) on the radially inner surface (21) of the annular drum (20) under controlled running conditions. The first driving device (30) has a rotation axis (Y) extending in a radially outer position with respect to the annular drum (20), so as to be able to access the annular drum (20) from the opposite side thereof.

A tyre for vehicle wheels comprises a tread band including a plurality of blocks and grooves that define in the tread band a void/solid ratio comprised between 0.4 and 0.65 and that form a tread pattern which is symmetrical with respect to an equatorial plane (X-X) of the tyre. The tread pattern includes a pair of circumferential grooves (20) arranged on opposite sides with respect to the equatorial plane and which define in the tread band a central annular portion and a pair of lateral annular portions arranged on opposite sides with respect to said central annular portion. The central annular portion comprises a plurality of circumferentially consecutive central blocks (30, 60) arranged astride of the equatorial plane and having a maximum width equal to, or greater than, 50% of a radial section maximum width of the tyre. The central blocks (30, 60) are separated from one another by a respective central transversal groove (45, 50) having a circumferential length less than that of a circumferentially adjacent central block (30, 60). Each central block (30, 60) comprises opposite axially outer faces (35, 65) inclined with respect to the equatorial plane by a predetermined angle. The axially outer faces (35) of a central block (30) are inclined with respect to a plane perpendicular to the equatorial plane on opposite sides with respect to the axially outer faces (65) of a circumferentially consecutive central block (60). Each lateral annular portion comprises a plurality of circumferentially consecutive lateral blocks (80, 90) separated from one another by a respective lateral transversal groove (85, 95).

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