Partially concave sidewall profiles for tubeless tyres - to enhance radial flexibility and hench ride comfort

摘要

A sidewall profile of a tyre carcass intended to fit on a wheel with conic, i.e. conversant rim seats, varies in thickness so that, in the fitted and inflated but unloaded condition, the outer surface of the sidewall is concave adjacent to the edge of the wheel. The maximum depth of the concavity is situated at a height above the wheel seal which is 15-20% of the radial depth between the wheel seat and the widest point of the tyre. The depth of the concavity is 1-10% of the chord length of the cavity. Used esp. for tubeless tyres used on rims designed to obtain a good seal, where the redn. in wall thickness due to the concavity compensates for the extra wall thickness provided at the edge of the tyre to ensure an adequate seat area. The redn. in wall thickness near the wheel rim cf. that of a tyre with a convex external surface profile enhances the radial flexibility of the tyre and improves ride comfort. Esp. claimed for use with tyres having steel cord reinforcement plies wrapped around the bead cord within a stiffener.