A method of producing a rubber compound for a tread portion designed to assume, with use, a porous surface with a 75 to 800 μm pore area. The method includes a first mixing step, in which a polymer base, recycled rubber, and silica are mixed together; and a second mixing step, in which a curing system is added and mixed to the compound from the first mixing step. 5 to 20 phr of recycled rubber is added at the first mixing step. The recycled rubber is 75 to 800 um in size, and is treated beforehand cryogenically. And the polymer base is selected from SBR, BR, NR and mixtures thereof. The invention also relates to a rubber compound for producing a tread portion, a tread portion and a winter tire comprising said tread portion.