Athenian cultural dominance continued throughout the Roman period, and the buildings added to the Agora reflect the educational role of the city, a role that ended only with the closing of the pagan philosophical schools by the Christian emperor Justinian in A.D. 529.
Bearing, in machine construction, a connector (usually a support) that permits the connected members to rotate or to move in a straight line relative to one another. Often one of the members is fixed, and the bearing acts as a support for the moving member. Most bearings support rotating shafts against either transverse (radial) or thrust (axial) loads.
The balls in a wheel bearing are hardened steel. They roll in precision-machinedgrooves and held together by the axle shaft or a threadfastener.They do not design pressed-in bearings to be disassembled. Any force applied to the hub will dimple the bearing races, which results in premature failure.