Bridgestone Tire Company Limited

Bridgestone Corporation

Norio Iwata

Hiroshi Kojima

Masao Nakamura

Takashi Takusagawa

Shigeo Makino

A heavy duty low-section pneumatic and a process for manufacturing the same are disclosed. This tire comprises a radial carcass toroidally extending between bead portions, a belt composed of a first and second belt layers successively superimposed around a crown portion of the carcass and a tread rubber having substantially the same width as the maximum width of the belt. In the belt, the first belt layer is composed of at least two cord plies each containing cords inclined at a small angle with respect to the equatorial plane of the tire, the cords of which being crossed with each other with respect to the equatorial plane, while the second belt layer is composed of at least one cord ply containing non-expansible or hardly expansible cords arranged in substantially parallel to the equatorial plane and extends over both sides of the first belt layer between the first belt layer and the carcass.

Heavy duty low-section pneumatic radial tire and a process for

A pneumatic tire having a tread of a lug type pattern is disclosed. In this type of the tire, the tread rubber has a composite structure of a cap rubber and a base rubber having a heat build-up property lower than that of the cap rubber and arranged on at least a shoulder portion of the tread just beneath the cap rubber. The base rubber has a thickness that an average thickness just beneath the lug is larger than that just beneath the lug groove in a conical plane imaged by taking as a general line a normal line drawn from the tread end to the inner surface of the tire in the radial section inclusive of a rotational axis of the tire.

Base-cap tread

Heavy-duty low-section pneumatic radial tire

A pneumatic tire for heavy duty vehicles comprises a tread divided by two circumferential zigzag grooves in a tread center zone including block patterns of elongated blocks circumferentially discontinuous with traverse grooves and side zones including circumferentially continuous ribs. The traverse grooves are provided in their mid portions 30-70% of their lengths with platforms making the grooves shallower 30-70% than their original depths. The pattern of the tread converts into a pattern of ribs formed by the circumferential zigzag grooves having branch grooves when the tread has worn more than 30-70%. The tire including the above tread pattern according to the invention is suitable for both use on paved hard roads and weak grounds.

Pneumatic tire for heavy duty vehicles

Vehicle tire

Growing community of inventors

Amagi, Japan

Norio Iwata