A method and system (10) for manufacturing a tyre tread (4) with lugs (6), the tread having a tread base (5), and a number of lugs (6) projecting upwards from the tread base (5); the method having the steps of: preparing a green-rubber blank tread (13) of constant thickness; applying rubber blocks (15) to the areas of the blank tread (13) where the lugs (6) are to be formed, each block varying lengthwise in cross section, so it is thinner at the centre and thicker at the side; and curing the blank tread (13), together with the blocks (15), in a curing mold (17) negatively reproducing the pattern of the tread (4).