Firstly, there are size limitations. The space that bearings can usually be installed is limited. In most cases, the shaft diameter (or bearing inner diameter) is limited by mechanical or other design considerations. So the selection of bearing type and size is determined by the inner diameter of the bearing. Therefore, the main dimension tables of standard bearings are compiled based on international standard inner diameter dimensions.

There are many dimensions of standard bearings. Standard bearings are used in the design of mechanical devices. (This design concerns whether bearings are easy to purchase. Here's a digression. Some imported bearings do have models in the catalog, but some non-standard bearings are not available in Chinese Mainland. Sometimes the future will take a long time, so the time cost and the cost of later replacement should be considered when selecting bearings.) The nature, size and direction of the load imposed on bearings are variable. Usually, the rated basic load is displayed on the size table. However, axial and radial loads are also important factors in selecting suitable bearings. When the size of the ball and needle roller bearings is equivalent, needle roller bearings usually have higher load capacity and can withstand greater vibration and impact loads.

The rotational speed is determined based on factors such as the type, size, accuracy, cage type, load, lubrication method, and cooling method of the bearing. The bearing table lists the allowable speed of standard precision bearings under oil lubrication and grease lubrication. Usually, deep groove ball bearings, self-aligning ball bearings, and cylindrical roller bearings are suitable for high-speed operation.

Bearing tolerances, bearing dimensional accuracy, and rotational accuracy are based on ISO and JIS standards. For machinery that requires high precision and high-speed operation, it is recommended to use bearings with precision level 5 or above. Deep groove ball bearings, radial thrust ball bearings, or cylindrical roller bearings are suitable for machinery with high operating accuracy. Rigidity, when the rolling element and raceway contact surface of the bearing are compressed, elastic deformation will occur. Some machines need to minimize elastic deformation. Roller bearings produce less elastic deformation than ball bearings.

In addition, in some cases, bearings need to be preloaded to increase rigidity. This program is commonly used for deep groove ball bearings, centripetal thrust ball bearings, and tapered roller bearings where the inner and outer rings are offset, the shaft is bent, the tolerance of the shaft or bearing housing changes, and fitting errors can all cause eccentricity of the inner and outer rings. To prevent excessive eccentricity, automatic self-aligning ball bearings, automatic self-aligning roller bearings, or self-aligning bearing seats are the preferred choices. Voice frequency and torque, as well as rolling bearings, are manufactured according to high-precision standards, resulting in low voice and torque. Deep groove ball bearings and cylindrical roller bearings are suitable for situations with special requirements for low noise and low torque.

Installation and disassembly, some applications require frequent disassembly and installation to ensure regular inspection and installation. Bearings that can be installed separately on the inner and outer rings, such as cylindrical bearings, needle roller bearings, and tapered bearings, are very suitable for this situation. The automatic self-aligning ball bearings with tapered holes and automatic self-aligning roller bearings, with the help of shaft sleeves, also simplify the installation process.