A pneumatic tyre of generally trapezoidal cross-section has conventional reinforcing plies e.g. of steel cord. In the border region where the side walls join the tread portion the tyre has a different reinforcement so that this region has a greater resistance to deformation. The border region, pref. of reinforced elastomer, of which part forms the tread portion but is not normally in contact with ground is more resistant to rotational forces so that it does'nt deform in a circumferential direction as the tyre rotates. Stresses set up in the tyre are therefore reduced.
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