Tire having ribs, circumferential grooves and sipe pairs

1. A tire comprising:

a tread pattern having ribs;

circumferential grooves which are at least one of tapered and generally V-shaped, wherein walls of each of the circumferential grooves have inwardly and outwardly curved portions which form a wavy and/or sinusoidal contour extending in a generally circumferential direction, wherein the walls extend to a tread surface and form first and second opening edges, the first opening edge having inwardly curved portions, outwardly curved portions, and spaced-apart straight portions, the second opening edge having inwardly curved portions, outwardly curved portions, and spaced-apart straight portions, and a theoretical center line perpendicular to an axis of rotation running along the circumferential direction completely residing between the first and second opening edges; and

sipe pairs which break up the first and second opening edges of each of the circumferential grooves,

wherein the sipe pairs define the straight portions; and

each straight portion extends from a sipe to another sipe and each outwardly curved portion extends from a sipe toward another sipe.

2. The tire of claim 1 , wherein:

the outwardly curved portions transition to the inwardly curved portions and the straight portions on the first opening edge are phase shifted from the straight portions on the second opening edge;

each of the straight portions is parallel to the circumferential direction; and

each of the walls having a variable wall contour.

3. The tire of claim 1 , wherein each of the circumferential grooves comprises an inwardly curved groove base whose depth is substantially constant in the circumferential direction.

4. The tire of claim 1 , wherein each of the circumferential grooves comprises an inwardly curved groove base having a wavy and/or sinusoidal contour extending in the generally circumferential direction.

5. The tire of claim 4 , wherein each of the first and second opening edges have a generally wavy and/or sinusoidal contour extending in the generally circumferential direction.

6. The tire of claim 1 , further comprising a plurality of wavy rib grooves arranged on the ribs.

7. The tire of claim 1 , wherein at least one of the circumferential grooves comprises a wavy or sinusoidal groove base that travels circumferentially and laterally crosses over the theoretical center line located between the first and second opening edges of the at least one circumferential groove.

8. The tire of claim 1 , wherein at least one of the circumferential grooves comprises a groove base that travels circumferentially and laterally crosses over the theoretical center line located between the first and second opening edges of the at least one circumferential groove.

9. The tire of claim 1 , wherein at least one of the circumferential grooves comprises a groove base that laterally crosses over, at various circumferential positions, the theoretical center line located between the first and second opening edges of the at least one circumferential groove.

10. The tire of claim 1 , wherein at least one of the circumferential grooves comprises a sinusoidal groove base that laterally crosses over, at regular intervals, the theoretical center line located between the first and second opening edges of the at least one circumferential groove.

11. The tire of claim 1 , wherein each of the circumferential grooves comprises a wavy or sinusoidal groove base that laterally crosses over the theoretical center line located between the first and second opening edges of each of the circumferential groove.

12. The tire of claim 1 , wherein the sipe pairs repeat with a same frequency as valleys of a sinusoidal groove base of at least one of the circumferential grooves.

13. The tire of claim 1 , wherein at least one of the circumferential grooves is defined by the first and second opening edges, each having the straight portions located between two of the inwardly curved portions, wherein the inwardly curved portions of the first opening edge are aligned circumferentially with the straight portions of the second opening edge and with peaks of a sinusoidal groove base of the at least one of the circumferential groove.

14. The tire of claim 1 , wherein the inwardly curved portions of the first opening edge are arranged directly opposite the straight portions of the second opening edge and the inwardly curved portions of the second opening edge are arranged directly opposite the straight portions of the first opening edge.

15. The tire of claim 1 , wherein each circumferential groove comprises a groove base having a wavy or sinusoidal contour, and wherein a distance between two outwardly curved peaks of the groove base is equal to a distance between center points defining a radius of each of two inwardly curved portions of one of the first and second opening edges.

16. The tire of claim 1 , wherein each circumferential groove comprises a groove base having a wavy or sinusoidal contour, and wherein a distance between two outwardly curved peaks of the groove base is equal to a distance between centers of two of the straight portions of one of the first and second opening edges.

17. The tire of claim 16 , wherein a center of each of the straight portions alternating between the inwardly curved portions of the first opening edge is aligned with a center of each inwardly curved portion on the second opening edge.

18. A tire comprising:

a tread pattern having ribs;

circumferential grooves which are at least one of tapered and generally V-shaped, at least one of the circumferential grooves comprising:

inwardly and outwardly curved groove wall portions,

a groove base having a wavy or sinusoidal contour extending in a generally circumferential direction,

first and second groove opening edges each having at least inwardly curved portions, outwardly curved portions, and straight portions alternating between the inwardly curved portions, and

a theoretical center line perpendicular to an axis of rotation running along the circumferential direction and completely residing between the opening edges; and

sipe pairs which break up the first and second groove opening edges of each of the circumferential grooves,

wherein the sipe pairs define the straight portions; and

each straight portion extends from a sipe to another sipe and each outwardly curved portion extends from a sipe toward another sipe.

19. The tire of claim 18 , wherein the inwardly curved portions of the first groove opening edge are aligned circumferentially with the straight portions of the second groove opening edge and with peaks of the wavy or sinusoidal groove base, and wherein each of the straight portions is parallel to the circumferential direction.

20. A tire comprising:

a tread pattern having ribs;

circumferential grooves which are at least one of tapered and generally V-shaped, each of the circumferential grooves comprising:

inwardly and outwardly curved groove wall portions,

an inwardly curved groove base having a wavy or sinusoidal contour which meanders substantially axially as it travels circumferentially, and

first and second groove opening edges each having outwardly curved portions arranged between straight portions and inwardly curved portions, wherein the straight portions of the first groove opening edge alternate between the inwardly curved portions of the first groove opening edge, are phase shifted from the straight portions of the second groove opening edge, are oriented parallel to the circumferential direction, and are arranged opposite the inwardly curved portions of the second groove opening edge, and a theoretical center line perpendicular to an axis of rotation running along the circumferential direction and completely residing between the first and second groove opening edges; and

sipe pairs which break up the first and second groove opening edges of each of the circumferential grooves,

wherein the sipe pairs define the straight portions, and

each straight portion extends from a sipe to another sipe and each outwardly curved portion extends from a sipe toward another sipe.