- Tyre for an agricultural vehicle, comprising a tread of width W surmounting a crown reinforcement, this crown reinforcement surmounting a carcass reinforcement and comprising a plurality of working layers (51, 52) each formed by a plurality of reinforcers that are oriented at one and the same mean angle with respect to the circumferential direction and are crossed from one layer to the next, this tread having a bearing surface on which a plurality of main lugs that are disposed around the tyre at a mean spacing P are formed on each side of the equatorial mid-plane (XX'), these main lugs being oriented at a mean angle other than zero to the axial direction of the tyre, this mean angle being defined as the angle of a straight line passing through the end points of a main lug, these main lugs extending from an edge of the tread as far as the equatorial mid-plane so as to form a V-shaped pattern, the tip of this V-shaped pattern being intended to come into contact with the ground first during running, these main lugs extending, on each side of the equatorial plane, axially beyond the axial end of the working layer of the axially widest crown reinforcement, this tread also comprising, on each side of the equatorial mid-plane, a plurality of secondary lugs that extend, on each side of the equatorial mid-plane, between an axial limit of the tread and an axial limit at a distance from the equatorial mid-plane by a width Ls of between 40% and 60% of the half-width (W/2) of the tread, each secondary lug being interposed between two main lugs and having a mean width Es of between 20% and 40% of the mean spacing P between two main lugs, each secondary lug extending axially beyond the axial end of the working layer of the axially widest crown reinforcement, this tyre being characterized in that: - the main lugs and the secondary lugs comprise, in the radial direction, a lens (21, 31) made of a first material, each lens extending axially on either side of the set of axial ends of the working layers (51, 52), each lens (21, 31) being surmounted by a second material that extends, in the new state, as far as the contact face of the main lugs and the secondary lugs, - the first material forming a lens in each main lug and each secondary lug has a viscous modulus G"1 and a complex modulus G ∗ 1, these moduli being measured to a simple alternating sinusoidal shear stress loading at a frequency of 10 Hz and at a temperature of 60°C, - the second material in each main lug and each secondary lug has a viscous modulus G"2 and a complex modulus G ∗ 2, these moduli being measured to a simple alternating sinusoidal shear stress loading at a frequency of 10 Hz and at a temperature of 60°C, - these moduli satisfying the following relationships: - the viscous modulus G"1 of the first material is at most equal to 60% of the viscous modulus G"2 of the second material, - the complex modulus G ∗ 1 of the first material is different from the complex modulus G ∗ 2 of the second material, the difference between these complex moduli being at most equal to 30% of the complex modulus G ∗ 2 of the second material. - the main lugs and the secondary lugs comprise, in the radial direction, a lens (21, 31) made of a first material, each lens extending axially on either side of the set of axial ends of the working layers (51, 52), each lens (21, 31) being surmounted by a second material that extends, in the new state, as far as the contact face of the main lugs and the secondary lugs, - the first material forming a lens in each main lug and each secondary lug has a viscous modulus G"1 and a complex modulus G ∗ 1, these moduli being measured to a simple alternating sinusoidal shear stress loading at a frequency of 10 Hz and at a temperature of 60°C, - the second material in each main lug and each secondary lug has a viscous modulus G"2 and a complex modulus G ∗ 2, these moduli being measured to a simple alternating sinusoidal shear stress loading at a frequency of 10 Hz and at a temperature of 60°C, - these moduli satisfying the following relationships: - the viscous modulus G"1 of the first material is at most equal to 60% of the viscous modulus G"2 of the second material, - the complex modulus G ∗ 1 of the first material is different from the complex modulus G ∗ 2 of the second material, the difference between these complex moduli being at most equal to 30% of the complex modulus G ∗ 2 of the second material.