Machine for fitting and removing wheel tyres for vehicles, comprising: - a bearing structure, - means for fastening and rotating the rim of a wheel for vehicles, - at least a tool-carrier unit associated mobile with said bearing structure and having at least a removal tool, - adjustment means comprising at least an articulated quadrilateral mechanism associated with said bearing structure and with said tool-carrier unit and suitable for adjusting the position of said tool-carrier unit with respect to said bearing structure, to place said tool-carrier unit into at least a work configuration, characterised in that it comprises: - memorisation means for memorising the position of said tool-carrier unit in an initially set work configuration, wherein said tool-carrier unit is substantially moved away from said bearing structure and said removal tool is arranged in proximity of said means for fastening and rotating, in correspondence to the side of a tyre of a wheel arranged on said means for fastening and rotating, and in the proximity of a edge of a rim of said wheel; - wherein said memorisation means comprises locking/release means of said articulated quadrilateral mechanism configured for locking said articulated quadrilateral mechanism when said tool-carrier unit is in said initially set work configuration, limiting the movement of said tool-carrier unit between said initially set work configuration and a configuration of minimum overall dimensions, wherein said tool-carrier unit is arranged in proximity of said bearing structure, and configured for releasing said articulated quadrilateral mechanism to position said tool-carrier unit in a different work configuration, - positioning means comprising an actuator element and associated with at least a first section of said articulated quadrilateral mechanism and with at least one between a second section of said articulated quadrilateral mechanism and said bearing structure, said positioning means being suitable for positioning said tool-carrier unit with respect to said bearing structure between said initially set work configuration and said configuration of minimum overall dimensions if it is necessary to remove the tyre of at least a new wheel of the same dimensions as the previous wheel. - a bearing structure, - means for fastening and rotating the rim of a wheel for vehicles, - at least a tool-carrier unit associated mobile with said bearing structure and having at least a removal tool, - adjustment means comprising at least an articulated quadrilateral mechanism associated with said bearing structure and with said tool-carrier unit and suitable for adjusting the position of said tool-carrier unit with respect to said bearing structure, to place said tool-carrier unit into at least a work configuration, - memorisation means for memorising the position of said tool-carrier unit in an initially set work configuration, wherein said tool-carrier unit is substantially moved away from said bearing structure and said removal tool is arranged in proximity of said means for fastening and rotating, in correspondence to the side of a tyre of a wheel arranged on said means for fastening and rotating, and in the proximity of a edge of a rim of said wheel; - wherein said memorisation means comprises locking/release means of said articulated quadrilateral mechanism configured for locking said articulated quadrilateral mechanism when said tool-carrier unit is in said initially set work configuration, limiting the movement of said tool-carrier unit between said initially set work configuration and a configuration of minimum overall dimensions, wherein said tool-carrier unit is arranged in proximity of said bearing structure, and configured for releasing said articulated quadrilateral mechanism to position said tool-carrier unit in a different work configuration, - positioning means comprising an actuator element and associated with at least a first section of said articulated quadrilateral mechanism and with at least one between a second section of said articulated quadrilateral mechanism and said bearing structure, said positioning means being suitable for positioning said tool-carrier unit with respect to said bearing structure between said initially set work configuration and said configuration of minimum overall dimensions if it is necessary to remove the tyre of at least a new wheel of the same dimensions as the previous wheel.