The tilting pad is the most common thrust bearing used in centrifugal compressors. The flat land and tapered land bearings are used less frequently. Figure 200-37 shows a tilting-pad bearing, consisting of a thrust collar (collar disk) attached to the rotor shaft, and a carrier ring which holds the pads. A button on the back of the pad allows the pad to pivot freely, thus allowing adjustment to varying oil velocity at different compressor speeds. A further refinement to the basic design is the self equalizing bearing shown in Figure200-38. An equalizing bar design allows the bars to rock until all pads carry an equal load.