Abstract: A method for simulating tire noise performance using a computer includes a step S1 of setting, using a finite number of elements, a tire model having a tread model portion provided with a tread groove, a step S2 of setting a road surface model using a finite number of elements, a step S4 of carrying out a rolling simulation to roll the tire model on the road surface model at least over a groove-grounded rolling distance between which the tread groove is brought into and out of contact with the road surface model; a step S5 of acquiring a surface coordinate value of the tread model portion in a time-series manner, and a step S7 of setting a sound space region around the tread model portion using the surface coordinate value of the tread model portion and of carrying out an aerodynamic simulation using the sound space region.

Abstract: A heavy duty pneumatic tire comprises a carcass ply of steel cords turned up around a bead core in each bead portion so as to form a pair of turned up portions and a main portion therebetween. The steel cords of the carcass ply are rubberized with a topping rubber having a hardness Ht1 of from 68 to 90 degrees. The bead core is composed of: a bead core main made of windings of a steel wire; a rubber coating penetrating into the bead core main and having a hardness Hb of from 78 to 90 degrees; and a bead core wrapping layer surrounding the bead core main and composed of at least one ply of parallel organic fiber cords rubberized with a topping rubber having a hardness Ht2 of from 70 to 90 degrees. The fineness of each of the organic fiber cords of the bead core wrapping layer is in a range of from 940 to 4200 dtex. The distances between the organic fiber cords of the bead core wrapping layer is in a range of from 0.3 to 1.4 mm.

Abstract: The present invention provides a rubber composition for an undertread, which has improved in processability, fuel economy, and tensile properties in a balanced manner, and also provides a pneumatic tire formed from the rubber composition. The present invention relates to a rubber composition for an undertread, including: a rubber component containing a modified natural rubber having a phosphorus content of 200 ppm or less; and carbon black and/or a white filler, wherein the modified natural rubber is contained in an amount of 5% by mass or more per 100% by mass of the rubber component.

Abstract: A run-flat tire comprises a tread portion having a left-right asymmetry tread pattern including an inboard tread edge and an outboard tread edge defining a tread width therebetween, a circumferentially extending inner crown main groove disposed in an inner crown area being 20% width of the tread width from a tire equator toward the in-board tread edge, a plurality of inner lateral grooves extending from the inner crown main groove to the in-board tread edge, a plurality of inner blocks separated by the inner crown main groove, inner lateral grooves and the inboard tread edge, wherein each inner block is not provided with any circumferential grooves, or is provided with at least one narrow circumferential groove having a groove width of less than 2.0 mm.

Abstract: A pneumatic tire has an asymmetric tread pattern. The width of an outboard shoulder main groove (3) is 3 to 4% of the tread width TW. The width of an inboard shoulder main groove (4) is 5 to 6% of TW. The width of an outboard crown main groove (5) is 6 to 7% of TW. The width of an inboard crown main groove (6) is 6 to 7% of TW. In each of the grooves (4, 5, 6), an outboard groove face's angle ?1 is more than an inboard groove face's angle ?2, wherein ?1 is 13 to 19 degrees, and ?2 is 9 to 14 degrees. In the groove (3), an outboard groove face's angle ?3 is 9 to 14 degrees, and an inboard groove face's angle ?4 is 5 to 8 degrees.

Abstract: A pneumatic tire comprises a tread portion provided with a tread element provided with a pair of sipes. Each sipe comprises a radially outer constant width part and a widening part extending radially inwardly from the constant width part while gradually increasing the width of the sipe and then extending to the radially inner end of the sipe while gradually decreasing the width of the sipe. Each of the paired sipes has an inside sidewall surface positioned toward the other of the paired sipes and an outside sidewall surface positioned away from the other of the paired sipes. The inside sidewall surface includes an inside curved bottom surface having a radius of curvature Rib. The outside sidewall surface includes an outside curved bottom surface having a radius of curvature Rob more than the radius of curvature Rib.

Abstract: A pneumatic tire with a specified rotational direction includes a tread portion provided with a pair of circumferentially extending crown main grooves disposed on both sides of the tire equator, a plurality of inclined lateral grooves each extending axially outside of the tire from each crown main groove to each tread edge toward the anti-rotational direction to separate a plurality of shoulder blocks between crown main grooves and tread edges, and a sipe, inclined lateral grooves with inclinations of 45-85 degrees with respect to the tire circumferential direction, each shoulder block with a heel-side edge and a toe-side edge which comes into contact with a road later than the heel-side edge in the specified rotational direction, in a planer view, the heel-side edge smoothly extending in a curved manner from a first end intersecting a groove wall of the crown main groove to a second end intersecting the tread edge.

Abstract: A heavy duty pneumatic tire includes main grooves that extend in the tire circumferential direction. A siped block is provided with at least one sipe to circumferentially subdivide the block into at least two block pieces that include at least one holed block piece provided with at least one small hole. Each small hole extends radially inwardly from the ground contacting surface of the holed block piece to its bottom at a depth in a range of from 30 to 100% of a depth of the main grooves. Each small hole has a round cross-sectional shape to have a maximum radius in a range of from 0.6 to 2.0 mm at the opening of the small hole in the ground contacting top surface. The total opening area of the at least one small hole is 2 to 12% of the overall area of the ground contacting top surface.

Abstract: The present invention has its object to provide a rubber composition that can be used for a tread to supply a tire having both low heat build-up property and good wet grip performance. The present invention relates to a rubber composition including: silica and a rubber component that contains a modified butadiene rubber having a vinyl content of 35% by weight or less and having, in a main chain thereof, a constitutional unit derived from a specific nitrogen-containing compound, wherein an amount of the modified butadiene rubber is 5 to 45% by weight per 100% by weight of the rubber component, and wherein an amount of the silica is 10 to 150 parts by weight per 100 parts by weight of the rubber component.

Abstract: A method includes a tubular carcass with core forming process (K1), a rubber laminate forming process (K2), and a tubular base tire forming process (K4). The forming process (K1) of forming a tubular carcass with bead core (6R3) on a first drum (20) comprises a tubular carcass forming step (K1a) to form a tubular carcass (6R2) by butt-jointing circumferential end faces of a carcass ply member (6R1) wound singly on the first drum (20), and a bead core joining step (K1b) to form integrally by diameter-expanding and pressing the tubular carcass (6R2) against the bead cores (5) outserted on the radially outer side. In the forming process (K2), rubber members for base tire (Ga) including an inner liner rubber member (G10a) are wound on a second drum (27) so as to form a rubber laminate (11).

Abstract: A rubber composition for a tire, and a pneumatic tire are provided in which the fuel economy, abrasion resistance, and deterioration resistance can be improved in a good balance. The present invention relates to a rubber composition for a tire, containing a rubber component that contains: a modified natural rubber having a phosphorus content of not more than 200 ppm; and butadiene rubber, wherein 60 to 95% by mass of the modified natural rubber and 5 to 40% by mass of the butadiene rubber are contained based on 100% by mass of the rubber component.

Abstract: The present invention has its object to provide a high performance studless tire, which has both good braking force and high handling stability on ice or snow, at higher productivity and at a lower price for customers. The studless tire comprises a tread made of a rubber composition containing 2.2 to 10 parts by mass of a fatty acid and/or a derivative of the fatty acid per 100 parts by mass of a rubber component, the tread having a JIS-A hardness of 50 or less.

Abstract: A pneumatic tire is provided on the tread portion (2) with a pair of crown circumferential grooves (3) that extending on either side of the tire equator (C); a pair of shoulder circumferential grooves (4) each extending between the crown circumferential groove (3) and a ground-contacting end (2t); a crown rib (5) extending between the crown circumferential grooves (3); middle ribs (6) each extending between the crown circumferential grooves (3) and the shoulder circumferential grooves (4); and shoulder ribs (7) each extending between the shoulder circumferential groove (4) and the ground-contacting end (2t). The groove volume ratio Rc of the crown rib, which is a ratio of the total volume of the grooves and sipes provided on the crown rib to the rib volume of the crown rib (5), the groove volume ratio Rm of the middle rib (6), and the groove volume ratio Rs of the shoulder rib (7) satisfy the relationship, Rc<=Rm<Rs.

Abstract: A pneumatic tire capable of reducing rolling resistance and discharging static electricity generated during running, wherein each of a tread rubber, a breaker rubber, and a sidewall, respectively, has a volume specific resistivity of 1×108 ?·cm or more, the pneumatic tire further including a conduction rubber embedded in the tread part so as to be at least partially exposed to a surface of the tread part, a coating rubber disposed on the upper part of the breaker part, a bead part rubber, and side part electroconductive rubber electrically connecting the conduction rubber to the beat part rubber, wherein each of the conduction rubber, the bead part rubber, the coating rubber and the side part electroconductive rubber has a volume specific resistivity of less than 108 ?·cm.

Abstract: A heavy duty tire comprises a tread portion provided with belt plies and circumferentially-extending main grooves, wherein a shoulder rib area between the axially outermost shoulder main groove and a tread edge is subdivided by a sub groove into an axially inner main rib zone and an axially outer sub rib zone. The main rib zone is provided with a high elastic modulus rubber layer extending along the axially outer edge of the main rib zone to form a part of the tread face and made of rubber having an elastic-modulus higher than that of rubber forming the tread face except for said part of the tread face. The axial width (W1a) of the high elastic modulus rubber layer is 0.3 to 0.6 times the axial width (W1) of the main rib zone.

Abstract: A thermoplastic elastomer composition which has excellent cleanability and is suitable for use as a medical rubber supply. It is characterized by comprising a rubber ingredient dynamically crosslinked with a crosslinking agent and a matrix which comprises a thermoplastic resin and in which the crosslinked rubber ingredient has been dispersed, the crosslinking agent comprising a triazine derivative.

Abstract: An apparatus for detecting a decrease in air pressure of a tire attached to a vehicle includes a rotation speed detection means for periodically detecting rotation speeds of tires of respective wheels of the vehicle; a rotation wheel speed ratio calculation means for calculating a rotation wheel speed ratio between front wheels and rear wheels of the vehicle; a wheel torque calculation means for calculating a wheel torque of the vehicle; an initialization means for obtaining a relation at a normal internal pressure between the wheel torque and the rotation wheel speed ratio; a comparison means for comparing the rotation wheel speed ratio with the rotation wheel speed ratio at a normal internal pressure obtained from the wheel torque and the relation; and a determination means for correcting the comparison result by a front-to-rear direction acceleration and determining whether there is a tire having a decreased air pressure or not.

Abstract: The present invention relates to a chafer using a rubber composition for a chafer comprising: (A) a diene rubber comprising (A1) 10 to 60% by mass of a butadiene rubber containing 2.5 to 20% by mass of a 1,2-syndiotactic polybutadiene crystal, (A2) 5 to 50% by mass of a tin-modified butadiene rubber polymerized with a lithium initiator and having 50 to 3000 ppm content of tin atoms, 5 to 50% by mass of vinyl bond amount and a molecular weight distribution of at most 2.0, and (A3) 20 to 75% by mass of a diene rubber other than the butadiene rubber (A1) and the tin-modified butadiene rubber (A2); and (B) 5 to 30 parts by mass of silica; and (C) 30 to 55 parts by mass of carbon black based on 100 parts by mass of the diene rubber components.