Adjustment of timken bearings Unlike other cylindrical bore radial bearings, the internal clearance of single row angular contact ball timken bearings and tapered roller bearings can only be established when one bearing is adjusted for the other. Usually these bearings are paired back-to-back or face-to-face, with one bearing ring displaced axially until a selected clearance or preload is reached. The choice of clearance or preload depends on the performance and operating conditions of the bearing arrangement. For details on bearing preload, see section 'Bearing Preload Control'. Therefore, the following recommendations relate only to internal clearance adjustment for bearing arrangements of angular contact ball bearings and tapered roller bearings. To achieve the appropriate clearance value during installation, it can be determined according to the bearing load and operating temperature conditions. Depending on the size and layout of the bearing, the materials of manufacture of the shaft and housing, and the distance between the two bearings, the initial clearance obtained during installation may be smaller or larger in actual operation. For example, the thermal expansion of the temperature difference between the inner and outer rings will cause the clearance to shrink during operation, so the initial clearance must be quite large to avoid the deformation of the timken bearing and its adverse consequences. Since there is a clear relationship between the radial and axial internal clearances of angular contact ball bearings and tapered roller bearings, only one value is required. Generally, the axial internal clearance is specified. This specified value can then be obtained from the zero clearance state by loosening or tightening the nut on the shaft or the threaded ring in the housing shaft hole, or inserting a calibrated washer between a bearing ring and its seat or gasket. The actual method used to adjust the clearance and measure the set clearance depends on the number of bearings to be installed. For example, one method is to use a dial indicator mounted on the hub to check the set axial clearance of the hub bearing arrangement. It is important that when adjusting a tapered roller timken bearing and measuring the clearance, the shaft or bearing housing needs to be rotated several times in different directions to ensure that the ball ends have proper contact with the guide lip on the inner ring. If the contact is improper, the measurement result will be inaccurate, and the intended adjustment purpose will not be achieved.