Pneumatic tires for off-road vehicles

Claim 1

A pneumatic off-road tire having improved cut resistant properties for use on vehicles running over unimproved surfaces, comprising: a carcass body composed of a plurality of rubberized ply layers superimposed one upon the other and each containing nylon cords embedded therein, the cords of approximately one-half of the carcass ply layers extending in an opposite direction to the cords associated with the remaining carcass ply layers to define a bias construction, and a breaker superimposed about said carcass body and composed of at least one rubberized layer each containing extensible reinforcing elements embedded therein, said extensible reinforcing elements comprising a filament bundle formed by assembling 3 to 30 helically formed steel filaments together without twisting and each having an average diameter D projected on a plane perpendicular to the axial line of a helix delineated by one pitch of said helically formed filament having a diameter φ in the range of 0.13 to 0.5 mm and, D≧3φ, said reinforcing elements being formed of material having a tensile strength of at least 140 Kg/mm 2 and having an elongation at breaking strength which is 0.25 to 1.4 times that of the nylon cord of said carcass body, said reinforcing element being inclined 30° to 55° with respect to the equatorial line of the tire, said breaker layer as a whole being extensible to prevent cut failure of the tire when running over unimproved surfaces.