The card wire comprises a plurality of teeth inclined at an angle with the rib portion. The teeth have a front portion and a back portion joining at the tip of the teeth; and a base segment connecting the front portion to the back portion of the preceding tooth. The front portion is the inner portion of the tooth leaning towards the rib portion. The back portion is the outer portion of the tooth. The front portion comprises at least two undercut segments. The second undercut segment is spaced further away from the tip of the tooth than the first undercut segment. Each undercut segment has an undercut angle, being the minimum of the angles with the longitudinal direction of the card wire, of the tangents to each point of the part of the undercut segment going—when observed from the tip—inwards from the front portion.