Abstract: A connecting element, preferably for fastening a wheel, or rim, to a hub of a vehicle, includes a body having a respective outer perimeter surface which extends along a respective imaginary profile, in particular an imaginary circular profile, there being formed, at the perimeter surface, respective elements for the engagement of corresponding elements or tool for screwing and/or unscrewing the connecting element, and screw thread elements for fastening, preferably to the vehicle hub. The engagement elements include a plurality of perpendicularly extending and circumferentially distributed engagement troughs which are recessed relative to the imaginary outer profile and each being separated from the adjacent trough by a respective outer perimeter transit zone. The outer transit zone has a width (r) which is less than the width (i) of the trough, and in particular, a width (r) which is less than half the width of the trough.