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Are there any requirements for the installation surface and location? Yes. If foreign objects such as iron shavings, burrs, or dust enter the bearing, it will cause noise and vibration during operation, and may even damage the raceways and rolling elements. Therefore, before installing the bearing, you must ensure that the installation surface and the installation environment are clean. Must bearings be cleaned before installation? The bearing surface is coated with rust preventive oil; it must be carefully cleaned using clean gasoline or kerosene, and then coated with clean, high-quality lubricant suitable for high speeds and high temperatures before it can be installed and used. Cleanliness has a significant impact on the lifespan of bearings as well as on vibration and noise levels. But we would like to remind you specifically that fully sealed bearings do not require cleaning or lubrication. How to choose grease? Lubrication has a crucial impact on the operation and lifespan of bearings; here we briefly introduce the general principles for selecting grease. Grease is made up of base oil, thickeners, and additives. Greases of different types, as well as different grades within the same type, exhibit significant differences in performance, with varying allowable rotation limits; this must be taken into consideration when making a choice. The performance of grease is primarily determined by the base oil; generally, low-viscosity base oils are suitable for low temperatures and high speeds, while high-viscosity ones are suitable for high temperatures and high loads. Thickeners also affect lubrication properties; the water resistance of thickeners determines the water resistance of grease. In principle, greases of different brands cannot be mixed, and even greases with the same thickener can have adverse effects on each other due to differences in additives. When lubricating bearings, is it true that the more grease applied, the better? It is a common misconception that the more grease applied when lubricating bearings, the better. Excessive grease in the bearings and bearing housings will cause excessive mixing of the grease, resulting in very high temperatures. The amount of lubricant filled into the bearing should be 1/2 to 1/3 of the internal space of the bearing; at high speeds, it should be reduced to 1/3. How to install and remove? During installation, do not strike the bearing’s end faces or the surfaces that are not under stress directly; instead, use pressure blocks, sleeves, or other installation tools to apply even force to the bearing. Never transmit force through the rolling elements. Applying lubricant to the mounting surface will make the installation smoother. If the interference is large, the bearing should be placed in mineral oil and heated to 80–90°C before installation; the oil temperature must be kept strictly below 100°C to prevent a decrease in hardness due to tempering effects and to avoid issues with dimensional recovery. When encountering difficulties during disassembly, it is recommended to use a disassembly tool to pull outward while carefully pouring hot oil on the inner ring; the heat will cause the inner ring of the bearing to expand, making it easier to remove. Is it true that the smaller the radial play of a bearing, the better? Not all bearings require the minimum operating clearance; you must select the appropriate clearance based on the conditions. According to the national standard 4604-93, the radial clearance of rolling bearings is divided into five groups: Group -2, Group 0, Group 3, Group 4, and Group 5. The clearance values increase in order from smallest to largest, with Group 0 representing the standard clearance. The basic radial clearance group is suitable for general operating conditions, normal temperatures, and common interference fits ； Bearings that operate under special conditions such as high temperature, high speed, low noise, and low friction should be equipped with a larger radial clearance ； For precision spindles and bearings used in machine tool spindles, a smaller radial clearance is advisable ； A small amount of operating clearance can be maintained in roller bearings. Additionally, for separate-type bearings, clearance is not an issue ； Finally, the operating clearance of a bearing after it is installed is smaller than its original clearance before installation, as the bearing has to rotate under certain loads, and there is also elastic deformation resulting from the bearing’s fit and the applied loads.