Needle Roller Bearings - High Load Capacity, Compact Size With Radial Orientation | Ideal For Engine Components And Bicycle Headsets

Needle Roller bearings are used in applications where compact size is required and radial space is limited. This is because these needle roller bearing only carry pure radial load and can not limit the axial displacement of shaft relative to the housing. They have a smaller cross-section, higher load-carrying capacity and greater rigidity, which in turn gives size and weight reductions in machinery. Needle bearings have a large surface area that is in contact with the bearing outer surfaces compared to ball bearings. Additionally there is less added clearance so they are much more compact. The typical structure consists of an inner race, a needle cage which orients and contains the needle rollers, the needle rollers themselves, and outer race. Radial needle bearings are cylindrical and use rollers parallel to the axis of the shaft. Thrust needle bearings are flat and use a radial pattern of needles.

Headsets in bicycles use a crooked pattern, so they are able to absorb both parallel and thrust power impacts. Needle bearings are heavily used in engine components such as rocker arm pivots, pumps, compressors, and transmissions. The drive shaft of a rear-wheel drive vehicle typically has at least 8 needle bearings (4 in each U joint) and often more if it is particularly long, or operates on steep slopes.