A hub blade assembly (1) for lawnmower is described, comprising a hub (2), a blade (3) and connecting means for reversibly connecting the blade (3) to the hub (2) which comprises at least one central through hole (4) and at least two lateral holes (5). The connecting means comprise balls (10) and springs (11) able to engage in said lateral holes (5) and a screw (8) able to engage in said central through hole (4). Said balls (100) are able to protrude from a lower opening (14) of the respective lateral hole (5) to reversibly engage in holes (18) of the blade (3). Said at least two lateral holes (5) are through holes, the connecting means comprise closing means (12, 23) of the lateral holes (5), each lateral hole (5) is able to reversibly house the closing means (12, 23), a spring (11) and a ball (10). (Fig. 6).
