A tire mold and a molding device for forming a sunken groove in a tire are provided. The molding device includes one or more rigid elements joined to a flexible member along an attachment point or line on the connecting surface of the rigid element. The flexible member is formed from a flexible material, preferably a superalloy, or hyperelastic material. If multiple rigid elements are utilized, the rigid elements are closely spaced together such that a portion of the opposed walls are in mating contact with an adjacent rigid element.