This invention relates to a pneumatic rubber tire having a puncture resistant rubber sidewall. The said tire sidewall is comprised of an outer, visible annular configured sidewall rubber layer and an inner (non-visible) annular configured sidewall rubber layer integral with and underlying said outer sidewall rubber layer, wherein said inner sidewall rubber layer contains a dispersion of short fibers, wherein said short fibers are substantially aligned in parallel relationship to each other and substantially parallel to the said annular configuration of said inner sidewall rubber layer. In a further aspect of the invention, said tire is comprised of a carcass which contains a rubber carcass ply comprised of a rubber encapsulated cord reinforcement of a plurality of cords wherein said cords are positioned in a radially disposed spaced apart substantially parallel relationship to each other, wherein said rubber carcass ply is integral with and underlies said inner rubber sidewall layer and wherein said short fibers of said inner rubber sidewall layer are substantially aligned in a perpendicular direction to said cords of said underlying carcass ply.