The radial needle roller bearings are designed to sustain very high loads in relation to their radial size. The diameter of the rolling elements is much smaller as opposed to their length (hence the name “needle bearings”). They come in a variety of versions, depending on whether they have an inner ring or a cage, or whether the outer ring is replaced by a cast or solid sheet metal cup (including those in which both rings are absent, in which case they are called “needle roller cages”).
They may be separable or they may have a solid outer to perform the task of supporting and rolling on surfaces. The radial needle roller bearing is able to carry purely radial loads, in view of the fact that it has to be accompanied by a thrust bearing (axial bearing) if the application requires it to tolerate axial loads too.