Aneedle roller bearingis a special type ofroller bearingwhich uses long, thincylindrical rollersresembling needles. Ordinary roller bearings' rollers are only slightly longer than their diameter, but needle bearings typically have rollers that are at least four times longer than their diameter.Like allbearings, they are used to reduce thefrictionof a rotating surface.
Compared toball bearingsand ordinary roller bearings, needle bearings have a greater surface area in contact with theraces, so they can support a greater load. They are also thinner, so they require lessclearancebetween theaxleand the surrounding structure.