Method of fitting pneumatic tires for wet and dry road conditions

A method of fitting right and left handed pneumatic tires to a vehicle, said tires having a tread pattern defined by a plurality of annular straight grooves extending over a whole circumference of each tire within a ground-contacting width of a tread surface thereof and a plurality of sub-grooves inclined obliquely to said straight grooves in the width direction and intersecting said straight grooves, all of said sub-grooves extending across the entire tread surface of each tire at a same direction of inclination relative to the tire circumferential direction, said sub-grooves in a ground-contacting surface of the tread of said right handed tire are directed obliquely to the right of a direction of travel and said sub-grooves in a ground-contacting surface of the tread of said left handed tire are directed obliquely to the left of a direction of travel, said method comprising the steps of:

• mounting the tires such that imaginary lines in the direction of sub-grooves at a ground-contacting tread surface of left- and right-hand tires confronting each other in the widthwise direction of the vehicle when viewed from above intersect each other solely in a direction toward a front of said vehicle in the direction of travel when a road surface is dry;
• removing the tires from the vehicle and remounting the tires in a reverse manner such the imaginary lines intersect each other solely in a direction toward the rear of said vehicle when the road surface is wet;
• and
• repeating the previous steps as appropriate upon each change of road surface condition to achieve optimum running performance of said tires.