Provided is a pneumatic tire where a total width (SW) and an outer diameter (OD) satisfy the relationship SW/OD0.3; an inner diameter (ID) and an outer diameter (OD) satisfy the relationship ID/OD0.7; as viewed in a tire meridional cross section, an area (X1) (mm.sup.2) of a first region (R1) and a periphery length (Y1) (mm) of an inner peripheral surface of the first region (R1) have a ratio X1/Y1 of 12 or greater and 30 or less; and an area X2 (mm.sup.2) of a second region (R2) and a periphery length (Y2) (mm) of an inner peripheral surface of the second region (R2) have a ratio X2/Y2 of 10 or greater and 15 or less.

A bias tire includes two or more carcass layers, at least one belt disposed outward from the carcass layers in a tire radial direction, a reinforcing rubber layer disposed between carcass plies included in a carcass layer of the carcass layers. A belt width of a widest belt with the widest width of the belts is 110% or more and 150% or less of a tread developed width, and a position of an upper end portion of the reinforcing rubber layer located outward in the tire radial direction is apart 3 mm or more from an end portion of the widest belt.

A pneumatic radial tire for a passenger vehicle according to the present invention has an appropriate relationship between a tire cross-sectional width SW and a tire outer diameter OD. Also, a method of using the pneumatic radial tire for a passenger vehicle according to the present invention is to use the above radial tire with at least specified internal pressure.

A pneumatic radial tire for a passenger vehicle according to the present invention has an appropriate relationship between a tire cross-sectional width SW and a tire outer diameter OD. Also, a method of using the pneumatic radial tire for a passenger vehicle according to the present invention is to use the above radial tire with at least specified internal pressure.

A run-flat tire includes a carcass, a tire side portion and a side reinforcement layer. The carcass bridges between a pair of bead portions. The tire side portion links between a bead portion and a tread portion. A carcass maximum width position of the tire side portion, at which the width of the carcass is at a maximum, is provided at the tire radial direction outer side relative to a position that is at 40% of the tire section height. The side reinforcement layer is provided at the tire width direction inner side of the carcass. A thickness of the side reinforcement layer at the position that is at 40% of the tire section height is not more than 65% of a thickness of the side reinforcement layer at the carcass maximum width position.

Provided is a tire to be mounted on a three-wheeled vehicle of a type that makes turns by tilting a tire(s) during turning, with which the steering performance in turning can be improved. This tire is a three-wheeled vehicle tire 10 to be mounted on a two-wheel side of a three-wheeled vehicle that is constituted by two front wheels and one rear wheel or one front wheel and two rear wheels and has a mechanism for tilting a tire(s) during turning. A radius of curvature (Rc) of a tread surface in a center region (C) is in a range of greater than 55% but 70% or less of a tire maximum width (W) where, on the tread surface at a tire widthwise cross-section, a region that is centered at the tire equator (CL) and comes into contact with the ground during straight running is defined as the center region (C) and regions on each side of the center region (C) are defined as shoulder regions (S).

The reinforcing element (45) comprises an assembly (49) made up: of a multifilament strand made of aromatic polyamide or aromatic copolyamide (46) and of a multifilament strand made of polyester (48). The two strands (46, 48) are wound in a helix around one another, and the reinforcing element (45) is twist-balanced. The twist factor K of the reinforcing element (45) ranges from 5.5 to 6.5 where K is defined by the formula: K=(RTi.sup.1/2)/957 in which R is the twist of the reinforcing element (45) expressed in twists per metre and Ti is the sum of the counts of the multifilament strands of the reinforcing element (45) in tex.

A tire includes a tread portion, a pair of bead cores, a carcass layer extended across the bead cores, and a belt layer disposed on an outer side of the carcass layer in a radial direction. A tire outer diameter OD (mm) is in a range 200?OD?660. A total tire width SW (mm) is in a range 100?SW?400. A tire internal volume V (m{circumflex over ()}3) is in a range 4.0?(V/OD)?10{circumflex over ()}6?60 with respect to the tire outer diameter OD (mm).

In a pneumatic tire, a two-dimensional code is provided on a surface of side rubber provided in a side portion. The two-dimensional code is formed of a dot pattern including two types of gray scale elements identifiably formed using surface irregularities. A two-dimensional code range in a tire radial direction in which the two-dimensional code is provided lies outward or inward of a bead filler rubber edge located outward of bead filler rubber in the tire radial direction.

A tire includes a tread, a pair of sidewalls, a pair of beads, and a carcass. Each bead includes a core and an apex. In the tire in the normal state, a ratio (HA/HS) of a distance HA in a radial direction from a bead base line to an outer end PA of the apex to a tire cross-sectional height HS may not be less than 20% and/or may not be greater than 30%, and an angle of a line segment connecting between the outer end PA of the apex and a center PM of a width, in an axial direction, of a contact surface of the apex at which the apex is in contact with the core, relative to the bead base line, may not be less than 45? and/or may not be greater than 55?.