Sumitomo Rubber Industries Limited

Shigehiko Suzuki

Itsuo Yasui

Sadaaki Naito

Eiji Nakasaki

Ryozo Okada

A pneumatic motorcycle tire provided with a spiral belt and a pair of axially spaced reinforcing layers radially inside of the belt to improve the cornering stability and straight running stability of a motorcycle.

Pneumatic motorcycle tire for improved cornering and straight running

A motorcycle tire in which the tread face is curved convexly so that the maximum cross-section width of the tire lies between axial edges of the tread portion includes a belt, and the belt comprises at least three plies, wherein the radially inner ply and radially outer ply are made of the same strip of rubberized parallel cords having a strip width of from 85 to 105% the tread width, and the middle ply is made of a strip of rubberized cords having a strip width which is different from that of the inner and outer plies.

Motorcycle tire with three belt plies

A radial tire for motorcycles which comprises: a carcass ply of organic fiber cords arranged radially at an angle of 70 to 90 degrees to the tire equator and turned up around bead cores to form two turned up portions and a main portion therebetween; and a belt disposed radially outside the carcass and inside a tread, wherein the radial height Ht of the radially outer edge of each carcass turned up portion is 0.5 to 1.2 times the radial height of the tread edge, both from the bead base. The belt is composed of three pieces, two lateral pieces and a central piece therebetween, each piece being made of at least one spirally wound cord having an elastic modulus of not less than 600 kgf/sq. mm and formed by winding spirally a ribbon of rubber in which the at least one cord is embedded. The width of the central piece of the belt is 0.1 to 0.6 times the tread width. The central piece is differed from at least one of the lateral pieces in respect of cord specification and/or cord arrangement.

Radial tire for motorcycle including spiral cord belt

Motorcycle tire

A radial tire for motorcycles which comprises: a carcass ply of organic fiber cords arranged radially at an angle of 70 to 90 degrees to the tire equator and turned up around bead cores to form two turned up portions and a main portion therebetween; and a belt disposed radially outside the carcass and inside a tread, wherein the radial height Ht of the radially outer edge of each carcass turned up portion is 0.5 to 1.2 times the radial height of the tread edge, both from the bead base. The belt is composed of three pieces, two lateral pieces and a central piece therebetween, each piece being made of at least one spirally wound cord having an elastic modulus of not less than 600 kgf/sq.mm and formed by winding spirally a ribbon of rubber in which the at least one cord is embedded. The width of the central piece of the belt is 0.1 to 0.6 times the tread width. The central piece is differed from at least one of the lateral pieces in respect of cord specification and/or cord arrangement.

A radial tire comprises a toroidal carcass extending between beads and turned up around bead cores, and a belt reinforcement disposed radially outside the carcass and inside a tread, wherein the belt reinforcement comprises a band layer formed by plural ribbons of rubber in which one cord or two parallel cords are embedded, the ribbons are wound spirally and continuously from one edge to the other edge of the tread to be arranged side by side, the ends of the ribbons are located at the edges of the band layer, and at each of the edges of the band layer the ends of the ribbons are shifted equiangularly in the circumferential direction of the tire.

Radial tire with band formed from plural ribbons

A motorcycle radial tire includes a carcass having at least one ply of radially arranged organic fiber cords turned up around a pair of bead cores, the radial height (Ht) of the radially outer edge of the carcass turned up portions being more than 0.6 times and less than 1.2 times the radial height (Hs) of tread edges, a first belt having one cord or a plurality of parallel cords wound spirally so that the windings thereof are laid at small angles with respect to the tire equator, a second belt having one ply of parallel organic fiber cords laid at at angle of 10 to 30 degrees with respect to the tire equator, a bead apex made of rubber having a JIS(A) hardness of 65 to 75 disposed between the main portion and each turned up portion of the carcass, and the radial height (Ha) of the radially outer edge of the bead apex from the bead base line being more than 0.5 times and less than 1.2 times the radial height (Hs) of the tread edges.

Motorcycle radial tire having a spirally wound belt

A belted radial tire for motorcycles which comprises: a pair of bead cores disposed one in each bead portion of the tire; a carcass extending between the bead portions through sidewall portions and a tread portion of the tire, the carcass having at least one ply of organic fiber cords arranged radially at an angle of 60 to 90 degrees to the tire equator; a tread disposed radially outside the carcass to define the tread portion; and a belt disposed radially outside the carcass and inside the tread and comprising two ply pieces made of at least one spirally wound cord having an elastic modulus of not less than 600 kgf/sq.mm, the above-mentioned tread curved so that the maximum cross section width of the tire lies between the tread edges, each of the two belt ply pieces formed by winding a ribbon of rubber, in which the belt cord is embedded, spirally around the carcass from the axially outer edge thereof toward the tire equator.

Belted radial tire for motorcycle

A radial tire for motorcycles which comprises: at least one carcass ply of organic fiber cords arranged radially at an angle of 85 to 90 degrees to the tire equator and turned up around the bead cores to form two turned up portions and a main portion therebetween; a tread disposed radially outside the carcass and curved so that the maximum cross section width of the tire lies between the tread edges; a belt disposed radially outside the carcass and inside the tread and having at least one spirally wound cord; and a bead apex disposed between the carcass main portion and each carcass turned up portion, wherein the belt is composed of at least one spirally wound cord having an elastic modulus of not less than 600 kgf/sq.mm; the bead apex is made of rubber having a JIS A hardness of 50 to 65 and extending radially outwardly from the bead core into the tread portion so that the extended portion is interposed between the belt and the carcass; the axial distance of the radially outer edge of the bead apex from the tire equator being greater than zero but less than 1/4 times the axial tread width; each carcass turned up portion extending radially outwardly from the bead portion into the tread portion over the tread edge; and the radial height of the radially outer edge of the turned up portion being larger than the radial height of the tread edge, both being measured from the bead base.

Growing community of inventors

Amagasaki, Japan

Shigehiko Suzuki