A tire building machine including an axially contractible and expandable drum is characterized by an annularly continuous center deck for the drum having a rigid, axially segmented yet continuous, generally cylindrical deck surface. The center deck includes a center support, end supports, and two symmetrically arranged sets of telescoping rings extending respectively between the center support and opposite end supports. The telescoping rings are axially expandable as the end supports move away from each other to form such rigid, axially continuous deck surface and axially collapsible into or upon one another as the end supports move toward each other. Each ring of the set has flanged ends forming both a stop and an annular sliding bearing surface for the adjacent ring. The rings and their flanges may be precisely formed so that each intermediate ring of the ring set has four annular supporting and sliding surfaces, contributing to the overall rigidity of the deck. Tire components may be applied and firmly stitched directly on the deck surface or an axially elastic sleeve may be employed. The sleeve, secured to each end support, has a substantially cylindrical outer diameter and an inner diameter conforming to the deck surface when axially expanded.