a hub locking mechanism for a wheeled vehicle is provided for selectively coupling and uncoupling driving and driven members . a clutch ring is in permanent engagement with one of the members and is axially moveable to engage the other member . engagement of the clutch ring and the engageable member is enhanced by the provision of tandem rows of engaging formations on the clutch ring and the engageable member . the mechanism for affecting movement of the clutch ring has an improved one piece friction shoe for the moving cam and an improved cage enclosing the clutch ring and actuating spring .