High Speed Greases

It is important to use a specialist high speed grease in fan bearings and other high-speed bearings. This is the best practice due to the high rotational speed of these bearings.

The problem is that the viscosity of the base oil used in a multi service grease is typically 150 or 220 cSt at 40°C. For the same load (torque) on the bearing, as the rotational speed increases the viscosity should decrease. The higher viscosity base oil of a multi service grease could lead to overheating, premature degradation of the grease and possible damage to the bearing. Bearing manufacturers offer a guide for maximum safe operating speeds.

The speed value (DN) for inner ring rotation, is the product of the ball bearing's bore in millimetres and shaft speed in rpm.

Compare DN values with the manufacturer's recommended value to determine type of lubrication and tolerance grade.

Speed factor = the internal diameter (ID) of the bearing in mm * the speed in rpm.

i.e. a 30 mm ID bearing with a rotational speed of 1000 rpm will have a speed factor of 30,000.

Usually oil lubrication is needed where speeds are very high (Speed factor is > 800,000) or where the temperature of the bearing is so great that there is a need for a cooling element from the oil.

Category: Greases & Gels
high speed spindle bearing grease