Abstract: A capstan wheel yarn feed device for textile machinery. A yarn tension detector (26) is provided in the yarn path downstream of a yarn outfeed eye (24), and is effective to move a yarn infeed guide (20) axially of the capstan wheel (10) in response to the detected presence or absence of tension in the yarn (16) delivered from the wheel. In this way the yarn is physically moved axially of the wheel when yarn demand ceases, to a zone which is of smaller perimeter and which optionally has a lower frictional coefficient. This removes the tendency of the wheel to continue to feed the yarn after the demand has ceased. Preferably the yarn is also clamped (34, 36) at the yarn infeed side of the wheel as demand ceases.