Angular contact ball bearings have a greater number of balls and higher capacities than deep groove ball bearings with the same boundary dimensions and are suitable for higher loads and speeds with proper lubrication. However, because of the absence of a flange on one side of the outer race, they are capable of supporting thrust loading in only one direction. This is why most applications employ two of the same bearing bearings facing opposite directions, often as a duplex pair. To obtain American BAC bearings capable of duplex mounting, they must be ordered “flush ground”, designated by the “G” suffix. “G” basically means “No axial clearance, no preload.” In cases where the tandem mounting is required, another bearing with thrust capability is usually employed on the shaft to take thrust or locate the shaft in the opposite direction as the pair.Duplex bearings are a set of two bearings on a shaft with the inner and outer rings clamped together with preload to attain greater axial and radial rigidity. Duplex bearings also used to achieve additional capacity when insufficient space radially for larger bearings.