Car tyre having a tread comprising a central portion (L1) located across an equatorial plane (X-X), a first shoulder portion (L2) located towards an outer side of the tyre and a second shoulder portion (L3) located towards an inner side of the tyre; first circumferential grooves axially delimiting the first shoulder portion (L2) and the second shoulder portion (L3) with respect to the central portion (L1) of the tread ; wherein: - said first shoulder portion (L2) and said second shoulder portion (L3) comprise a plurality of first transverse grooves having a first end located substantially at the 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; - the number of said first transverse grooves of the first shoulder portion (L2) is lower than the number of said first transverse grooves of the second shoulder portion (L3); - said central portion (L1) comprises at least one circumferential rib , comprising a plurality of second transverse grooves ; - said central portion (L1) comprises a second circumferential groove and two circumferential ribs ; - each circumferential rib of the central portion (L1) has a predetermined void-to-rubber ratio, said void-to-rubber ratio being greater in the rib which is closest to the inner side of the tyre than the other ribs; characterized in that : - said second transverse grooves have a maximum width smaller than or equal to about 3 mm and define in said at least one circumferential rib a void-to-rubber ratio smaller than 0.06; - said second transverse grooves comprise a first substantially straight segment extending over at least 50% of the total extension of the second transverse grooves ; said first substantially straight segment has an extension smaller than 95% of the total extension of the second transverse grooves . - said first shoulder portion (L2) and said second shoulder portion (L3) comprise a plurality of first transverse grooves having a first end located substantially at the 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; - the number of said first transverse grooves of the first shoulder portion (L2) is lower than the number of said first transverse grooves of the second shoulder portion (L3); - said central portion (L1) comprises at least one circumferential rib , comprising a plurality of second transverse grooves ; - said central portion (L1) comprises a second circumferential groove and two circumferential ribs ; - each circumferential rib of the central portion (L1) has a predetermined void-to-rubber ratio, said void-to-rubber ratio being greater in the rib which is closest to the inner side of the tyre than the other ribs; characterized in that : - said second transverse grooves have a maximum width smaller than or equal to about 3 mm and define in said at least one circumferential rib a void-to-rubber ratio smaller than 0.06; - said second transverse grooves comprise a first substantially straight segment extending over at least 50% of the total extension of the second transverse grooves ; said first substantially straight segment has an extension smaller than 95% of the total extension of the second transverse grooves . - said second transverse grooves have a maximum width smaller than or equal to about 3 mm and define in said at least one circumferential rib a void-to-rubber ratio smaller than 0.06; - said second transverse grooves comprise a first substantially straight segment extending over at least 50% of the total extension of the second transverse grooves ; said first substantially straight segment has an extension smaller than 95% of the total extension of the second transverse grooves . <EOS>