Cylindrical roller bearings use rollers as rolling elements, and therefore have a higher load capacity in comparison to same dimension ball bearing. The rollers are guided by the ribs of the inner or outer ring. The inner and outer rings can be separated to facilitate assembly, and both can be fit with shaft or housing tightly. If there are no ribs, either the inner or the outer ring can move freely in the axial direction. Cylindrical roller bearings are therefore ideal to be used as so-called “free side bearings” that absorb shaft expansion. In the case where there is a rib, the bearing can bear a slight axial load between the end of the rollers and the rib. Cylindrical roller bearings include the ‘HT’ type which incorporates the modified shape of roller end face and ribs for increasing axial road capacity. And the ‘E’ type with a special internal design for enhancing radial load capacity. The E type is standardized for small-diameter sizes.