Tread Structure of an Agricultural Vehicle Tire

Agricultural vehicle tire having tread () with bearing surface () on which main lugs () and shorter secondary lugs () are formed on each side of the equatorial mid-plane (XX′), each secondary lug () interposed between two main lugs (). The main lugs () and secondary lugs () make up, in the radial direction, a lens () of a first material, each lens () surmounted by a second material extending to the contact face of the main lugs and the secondary lugs. The viscous modulus G″ of the first material is at most 60% of the viscous modulus G″ of the second material. The complex modulus G* of the first material differs from the complex modulus G* of the second material, the difference between these complex moduli being at most 30% of the complex modulus G* of the second material.