The ultimate speed of the bearing is the maximum speed that can be achieved when the bearing is running. It depends mainly on the relationship between the heat generated by the friction during the running of the bearing and the heat discharged, and the bearing material, structural dimensions, clearance, load, The material and structure of the cage and the guiding method, the lubrication method, the amount of lubricant, and the cooling condition of the bearing are closely related.

In general, the limit speed of a single set of bearing grease lubrication and oil lubrication is given in the bearing sample. The applicable conditions are: standard structure, normal grade accuracy, and opening of the basic group clearance. Bearing; sufficient lubrication condition; equivalent dynamic load is less than 10% of bearing dynamic load; at 20 °C ambient temperature, bearing temperature rise is 50 °C; radial bearing only bears radial load, thrust bearing only bears axial load . If the actual operating conditions are different from the applicable conditions above, the actual maximum operating speed will be lower than the reference limit speed value given in the sample. The limit speed of double or triple bearings can generally reach 60%-80% of single bearing.

Increasing the bearing accuracy and appropriately increasing the bearing clearance can increase the limit speed of the bearing to a certain extent, but the specific increase is difficult to quantify; the cage is made of lightweight material or the cage with special structure is designed. More efficient lubrication can greatly increase the limit speed of the bearing, up to 3 to 4 times the limit speed given by the sample.