Very low friction is one of the major characteristics of rolling element bearings. The frictional moments of rolling bearings are usually so small that they can almost always be neglected in practice, although for some applications even small frictional resistance must be considered.
The frictional resistance for all rolling bearings is dependent not just upon the bearing type and size, but includes specific application data like speed, load and lubrication..
According to their internal contacting geometry deep groove ball bearings in general perform with very low friction which makes them suitable for high speeds. A comparatively high friction, however, is generated with bearing types like cylindrical roller thrust bearings etc.
Contacting seals (suffixes -RS, -2RS, -RSR, -2RSR etc.) always generate additional friction due to the preloading of their sealing lips, unlike shields (suffixes -Z, -2Z), that build a non-contacting gap seal to the inner ring and subsequently do not generate additional friction.
An estimation of the frictional moment providing results of sufficient practical accuracy is possible by applying the following formula: