An extrusion head for producing, for example, tread strips for vehicle tires comprises a stationary central portion and two pivotable outer portions. Between each outer portion and the central portion, in the operative position of the head, insert members are interposed. Flow channels for the different materials used to make the tread strip and defined between the insert members and the central and outer portions of the head. The insert members are made displaceable by being detachably affixed to push-rods which are hydraulically, pneumatically or mechanically actuated. This provides for movement of the insert members, when the outer portions are pivoted away from the central portion, into a position which permits unhindered access to all sides of the insert members and permits the rapid cleaning and/or replacement thereof.