A number of factors affect speed limitation such as temperature, load, vibration, radial play, retainer, lubricant, ball material and closures. The speeds quoted in our catalogue pages are only approximate and valid for bearings used on a horizontal shaft with a metal cage, standard tolerance grade and radial play, medium loading, rotating inner ring and suitable lubricant (see below). Vertical shaft applications will necessitate a reduction of approximately 20 percent. Temperature excesses and heavy loadings will also require slower speeds. Bearings fitted with contact seals cannot achieve the same speeds due to increased friction between seal lip and bearing inner ring. The choice of lubricant may also have a significant effect on the speed rating. The maximum rpm at which a lubricant can effectively operate varies from type to type. The following adjustment factors are approximate and are based on bearings with a metal crown or ribbon cage. The maximum speed of a bearing can be increased by the use of a delrin or phenolic cage provided a suitable lubricant is used. The use of ceramic balls will increase bearing speed by up to 30 percent.