Car tyre

A car tyre having a tread, comprising:

• a central portion located across an equatorial plane;
• a first shoulder portion located towards an outer side of the tyre;
• and
• a second shoulder portion located towards an inner side of the tyre,
• the central portion being separated from said shoulder portions by two first circumferential grooves having a respective width in a range between about 5 mm and about 16 mm,
• wherein:
• said first shoulder portion and said second shoulder portion comprise a plurality of first transverse grooves having a first end located substantially at a respective edge of the tread, having a width greater than or equal to about 4 mm and an axial extension equal to at least 50% of the width of the shoulder portion in which they are located,
• said two first circumferential grooves are a first circumferential groove facing towards the outer side of the tyre and a first circumferential groove facing towards the inner side of the tyre, the first circumferential groove facing towards the outer side of the tyre having a width smaller than the width of the first circumferential groove facing towards the inner side of the tyre,
• the number of said first transverse grooves of the first shoulder portion is lower than the number of said first transverse grooves of the second shoulder portion,
• said central portion comprises at least two straight second circumferential grooves that in combination with the two first circumferential grooves define three circumferential ribs,
• said three circumferential ribs comprise a central circumferential rib that passes through the equatorial plane, an outer circumferential rib positioned towards the outer side of the tyre, and an inner circumferential rib positioned towards the inner side of the tyre,
• the central circumferential rib comprises a plurality of blocks circumferentially defined by second transverse grooves that extend over an entire width of said rib,
• a number of the second transverse grooves of the central circumferential rib is equal to the number of said first transverse grooves of the first shoulder portion, and
• said second transverse grooves have a maximum width smaller than or equal to about 3 mm and define in the central circumferential rib a void-to-rubber ratio smaller than 0.06.

A car tyre having a tread, comprising:

• a central portion located across an equatorial plane;
• a first shoulder portion located towards an outer side of the tyre;
• and
• a second shoulder portion located towards an inner side of the tyre,
• the central portion being separated from said shoulder portions by two first circumferential grooves having a respective width in a range between about 5 mm and about 16 mm,
• wherein:
• said first shoulder portion and said second shoulder portion comprise a plurality of first transverse grooves having a first end located substantially at a respective edge of the tread, having a width greater than or equal to about 4 mm and an axial extension equal to at least 50% of the width of the shoulder portion in which they are located,
• said two first circumferential grooves are a first circumferential groove facing towards the outer side of the tyre and a first circumferential groove facing towards the inner side of the tyre, the first circumferential groove facing towards the outer side of the tyre having a width smaller than the width of the first circumferential groove facing towards the inner side of the tyre,
• the number of said first transverse grooves of the first shoulder portion is lower than the number of said first transverse grooves of the second shoulder portion,
• said central portion comprises at least two straight second circumferential grooves that in combination with the two first circumferential grooves define three circumferential ribs,
• said three circumferential ribs comprise a central circumferential rib that passes through the equatorial plane, an outer circumferential rib positioned towards the outer side of the tyre, and an inner circumferential rib positioned towards the inner side of the tyre,
• each rib of the three circumferential ribs comprises a respective plurality of blocks circumferentially defined by second transverse grooves that extend over an entire width of said rib,
• a number of the second transverse grooves of the outer circumferential rib is equal to the number of said first transverse grooves of the first shoulder portion,
• a number of the second transverse grooves of the inner circumferential rib is equal to the number of said first transverse grooves of the second shoulder portion, and
• said second transverse grooves have a maximum width smaller than or equal to about 3 mm and define in each of said three circumferential ribs a void-to-rubber ratio smaller than 0.06.