Abstract: A breaker reinforcing tape for belted pneumatic tires, a method of making such tape, and a method of constructing such tires therewith, are disclosed. The tape includes a generally sinusoidally crimped strip of uncured rubber and a plurality of similarly crimped parallel cords having their undulations following and nesting in the undulations of the crimped strip, the cords at successive apexes being secured to successive apexes of the strip. A second uncured rubber strip in a flat condition is secured to alternate ones of the apexes of the undulations of the array of cords and the crimped strip at one face of the latter. At least one frangible element is interposed in a fixed and substantially flat condition between the crimped and flat strips for releasably reinforcing and stabilizing the flat strip against inadvertent expansion that would prematurely reduce the amplitude and frequency of the undulations of the crimped strip and its associated cords.