One of the two types of rolling, or antifriction, bearings, the other being the ball bearing. Like a ball bearing, a roller bearing has two grooved tracks, but the balls are replaced by rollers. The rollers may be cylinders or shortened cones. If the rollers are cylindrical, only radial loads (perpendicular to the axis of rotation) can be carried, but with conical rollers both radial and thrust, or axial, loads (parallel to the axis of rotation) can be carried. In a given space, a roller bearing can carry a greater radial load than a ball bearing can.