Radial carcass tire employing carcass expansion limiting block

A tire with a radial carcass reinforcement anchored on both sides to at least one bead ring and with a tread reinforcement formed of at least two superimposed work plies of wires or cables which are parallel in each ply and crossed from one ply to the other forming acute angles of between 10.degree. and 45.degree. with the longitudinal direction of the tire, the tread reinforcement, seen in meridian cross section, being parallel to the radial carcass reinforcement along an equatorial zone and being arranged between the radial carcass reinforcement and the tread, characterized by the fact that between the radial carcass reinforcement and the tread reinforcement in the equatorial zone along which the tread reinforcement is parallel to the radial carcass reinforcement there is arranged a limiting block formed of two superimposed plies of wires or cables of low extensibility which are parallel to each other in each ply and crossed from one ply to the other forming with the longitudinal direction angles of opposite sign, each being both other than zero and less in absolute value than one-half of the smallest angle of the wires or cables of the work plies, the axial width of the limiting block being both between 60% and 100% of the axial width of the equatorial zone along which the tread reinforcement is parallel to the radial carcass reinforcement and, for a ratio H/B of between 0.3 and 1.2, between a maximum value M.sub.b =(-80 H/B)+100 and a minimum value m.sub.b =(-48 H/B)+60 expressed in percentage of the overall maximum axial width B of the tire, and by the fact that for a ratio H/B of between 0.3 and 1.2, the axial width of the narrowest work ply or the common axial width of the work plies of the tread reinforcement is between a maximum value M.sub.a =(-50 H/B)+110 and a minimum value m.sub.a =(-30 H/B)+85 expressed in percentage of the overall maximum axial width B of the tire, H being the overall radial height of the tire on a rim and wherein the wires or cables of low extensibility of the limiting block have a relative elongation less than 0.2% under a load equal to 10% of their rupture load.