A mould (10) for a tire, comprising two shells (30) that are each intended to mould a lateral sidewall of the tire, a ring of sectors (20) intended to mould a tread of the tire, each sector (20) of the ring of sectors comprising a radially inner face (21) having a moulding lining (22). The mould (10) has microstructures (50) that are designed to fill a clearance between two moulding linings (22) of adjacent sectors (20) and/or between a moulding lining (22) of one sector (20) and a shell (30), when the mould is closed.