Bridgestone Corporation

Takashi Kaneko

Kenjiro Yamaya

Kazuo Hayashi

Yutaka Naruse

Yutaka Yamaguchi

Hiroshi Nishigata

A pneumatic radial tire having excellent steering stability, resistance to hydroplaning and noise reduction comprises a carcass, a belt and a tread portion provided with a plurality of tread grooves and having an aspect ratio of not more than 50%, in which a ratio of ground contacting width of tire tread to rim width under measuring conditions defined in ETRTO is less than 0.85 and a negative ratio is not more than 25%.

Pneumatic radial tire having small negative ratio and small tread ground contacting width to rim width

A pneumatic radial tire comprises a radial carcass, a belt, and a row of many blocks having different lengths along a circumference of a ground contact region under pitch variation defined in a tread rubber of the tread portion by at least two straight main grooves and a plurality of lateral sub-grooves extending between the mutual main grooves at an inclination angle of less than 90&deg; with respect to the circumference of the ground contact region, in which the block row satisfies such relationships that an inclination angle &phgr; of an edge of a long-pitch block is larger than that &phgr; of an edge of a short-pitch block and an inclination angle &agr; of each block wall face of a long-pitch block is larger than that &agr; of each block wall face of a short-pitch block, or further an inclination angle &bgr; of a block wall face of a short-pitch block is larger than that &bgr; of a block wall face of a long-pitch block.

Pneumatic radial tire including blocks having different lengths

The present invention provides a method for adjusting vehicle wheel alignment in which a positional angle of a wheel corresponding to the characteristics of a tire can be set easily, running stability suited for an actual road surface can be obtained, and one-sided wear can be reduced. The method for adjusting vehicle wheel alignment includes the steps of: placing a wheel of a vehicle, which is an object of adjustment, on a tire driving surface on which a step of a predetermined height is formed at at least one place along a rotating direction in which the tire driving surface is driven by a rotational force; measuring variations in forces applied in the rotating direction of the tire driving surface and a rotation axis direction which is orthogonal to the rotating direction at the time the wheel passes over the step while the tire driving surface is being driven/rotated so that the wheel is rotated in a proceeding direction of the vehicle; and adjusting a positional angle of the wheel, on the basis of results of measurement, such that a variation in lateral force generated by a vehicle tire when the wheel passes over the step is a minimum.

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Hannou, Japan

Takashi Kaneko