Load ratings for bearings are expressed in Kgf (kilogramme force) on this website. That is the force exerted by a mass of 1 kilogramme at the Earth's surface. You will often see force expressed in Newtons elsewhere. A Newton is defined as the force that will accelerate a mass of one kilogram at the rate of one meter per second per second (or 1 m/s²). Since the force of gravity at the Earth's surface is 9.80665 m/s², 1 Kgf = 9.80665 Newtons but, to keep it simple, we say 1 Kgf = 10 Newtons.
Dynamic radial load rating
The official explanation for this is... "The dynamic load rating is that constant stationary radial load which 90% of a group of identical chrome steel bearings, with only the inner ring rotating, can endure for one million revolutions before the first signs of fatigue develop". Yes, 1 million revolutions sounds a lot but is it really? If you take a bearing running at 5000 rpm with the max dynamic load applied to it, it will last for 1,000,000 revs divided by 5000 = 200 minutes or 3 hours and 20 minutes!! This should tell you that these figures are used in the calculation of life ratings but bearings should not be subjected to anywhere near such loads in normal application unless you don't expect them to last very long. If long life is required, it is preferable to limit the actual load to between 6% and 12% of a bearing’s dynamic load rating. Heavier loads can be tolerated but life will be shortened. AISI440C/KS440 stainless steel bearings will support approximately 80% -
Static radial load rating
This represents the purely radial load (or axial load for thrust bearings) which will cause a total permanent deformation of the balls or raceway equal to one ten-
The load capacity of a bearing may be limited by the lubricant. Certain lubricants are only suitable for light loads while others are designed for high load applications. Load ratings are higher for full complement bearings (see Retainer). The axial load capacity of a radial ball bearing can be increased by specifying loose radial play.
Axial load rating
Heavy duty bearing types such as 6200 or 6300 series may take axial loads of up to 50 percent of the static radial load rating. Thin-
Full complement ball bearings use a filling slot machined into the inner and outer rings. Under axial load, this slot can interfere with ball rotation so full complement bearings are not recommended for axial loads.
For load ratings, please follow the info link to our technical drawings in the PRODUCT TABLES