Tyre for a vehicle intended to carry heavy loads, this tyre having a crown comprising a tread intended to be in contact with a roadway when rolling, this crown being continued on either side by sidewalls, these sidewalls being connected to beads intended to come into contact with a wheel, this tyre comprising a carcass reinforcement having reinforcers, this carcass reinforcement extending from one bead to the other, passing via the sidewalls and the crown of the tyre, this tyre being provided, on an external surface of at least one sidewall, with a device for protecting against external attack, this protective device being made up of a plurality of protuberances (21, 22) distributed in a number N of circular lines (C1, C2) concentric with the axis of rotation (XX') of the tyre, this number N being at least equal to two, each protuberance (21, 22) having an external geometry such that any external profile of this protuberance (21, 22), as seen in any radial section plane containing the axis of rotation (XX') of the tyre, is a convex profile having a high point (Pi) defined as being the point furthest from the external surface of the sidewall on which the protuberance (21, 22) is formed, each protuberance (21, 22) having an external surface, the geometry of which does not have any edge corners, apart from the intersection thereof with the external surface of the sidewall on which the protuberance (21, 22) is formed, in order to avoid any slope discontinuity, the external profile of each protuberance (21, 22) comprising a first part (211, 221), referred to as extensive part, with a height that increases regularly and uniformly with respect to the external surface of the sidewall of the tyre on which the protuberance (21, 22) is formed, this extensive part being continued from the high part (Pi) by a second part, referred to as reduced part, with a height that decreases regularly and uniformly with respect to the external surface of the sidewall of the tyre on which the protuberance (21, 22) is formed, this tyre being characterized in that, for each protuberance (21, 22), the high point (Pi) of any external profile is offset in the meridian direction (MM') with respect to the median position of the protuberance (21, 22), this median position, for each radial section plane, being defined as the position situated half-way between intersection points (Ai, Bi) of the protuberance (21, 22) with the external surface of the sidewall on which the protuberance (21, 22) is formed in this same radial section plane, and in that - the protuberances of a first circular line partially overlap the protuberances of an adjacent circular line in the circumferential direction (NN'), such that a radial plane tangent to a protuberance situated on the first circular line is tangent to or intersects a protuberance situated on the adjacent circular line such that the protuberances of the first circular line and the protuberances of the adjacent circular line close the passage in the meridian direction (MM') around the entire circumference of the tyre, and in the meridian direction (MM'), such that there exists at least one circle centred on the axis of rotation (XX') of the tyre, which intersects the protuberances of the first circular line and the protuberances of the adjacent circular line. - the protuberances of a first circular line partially overlap the protuberances of an adjacent circular line in the circumferential direction (NN'), such that a radial plane tangent to a protuberance situated on the first circular line is tangent to or intersects a protuberance situated on the adjacent circular line such that the protuberances of the first circular line and the protuberances of the adjacent circular line close the passage in the meridian direction (MM') around the entire circumference of the tyre, and in the meridian direction (MM'), such that there exists at least one circle centred on the axis of rotation (XX') of the tyre, which intersects the protuberances of the first circular line and the protuberances of the adjacent circular line.