The Yokohama Rubber Co., Ltd.

Hisao Katoh

Susumu Imamiya

Yukio Tozawa

A pneumatic radial tire for passenger cars and heavy duty use is disclosed, which tire has a rubber coated steel cord layer in its belt portion. The cord consists of a pair of steel filaments whose preform ratio 'K' is set in the range of 2.05-K.sub.1 .ltoreq.K.sub.2 &lt;2.50-K.sub.1. Conformance to this preform ratio 'K' provides filaments with periodically alternate contact and non-contact regions longitudinally of the cord.

Pneumatic radial tire with 1x2 steel belt cord

A pneumatic radial tire for automotive vehicles comprising a least one rubber coated steel cord consisting of a pair of intertwisted filaments and having a flatness ratio f in the range of 0.6.ltoreq.f .ltoreq.0.9, where f is defined by 2d/h, where d is a diameter of a filament and h is the maximum diameter of the flattened 1.times.2 cord. This cord is obtained by deforming the cord with a force applied transversely and unidirectionally over its length.

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Hiratsuka, Japan

Hisao Katoh