Pneumatic tyre and wheel rim assemblies

Abstract

Abstract 1351443 Pneumatic tyre and wheel rim assemblies DUNLOP HOLDINGS Ltd 21 May 1971 [3 June 1970] 26702/70 Heading B7C A pneumatic tyre and wheel rim assembly comprises a tyre having a pair of annular beads each provided with a rubber apex strip 5 of hardness at least 60 degrees BS and a reinforcing strip 7 extending around the bead and into the radially inner sidewall region, the ratio of the maximum internal axial width A-A of the tyre to the distance R-R between the axially outermost rim contacting points on the tyre being in the range from 125 to 200% when the tyre is inflated to its normal working pressure. The distances, measured along the sidewall, from the centre of cross-section of the bead core to the edges of the reinforcing strip and the radially outer edge of the apex strip are, in the case of a cross ply tyre, from 85 to 160%, preferably 100 to 160%, of the axial distance X between the centre of the bead core 1 and the point of maximum internal width A and, in the case of a radial ply tyre, are from 140 to 210%. The reinforcing strip consists of a single layer of parallel cord fabric, the cords, e.g. of steel, glass fibres or carbon fibres, having a bias angle of 30 degrees or lower, preferably 17 to 30 degrees to the circumferential plane measured relative to a tangent to a circumference adjacent the bead core. Each bead core consists of a spirally wound metal strip. Alternatively each core may consist of a plurality of wires. A further strip (chafer) which is more flexible than the reinforcing strip may be positioned outside the reinforcing strip in the bead; this strip may be of rubber. The aspect ratio of the tyre is in the range of 25 to 65%.

Inventors

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Bibliographic Details