Patent FR-2800015-A1 (FR)
Title: Tire for use with high performance automobiles has a center groove around the circumference with structured inner and outer tread zones of longitudinal and lateral grooves to eject water when driving in wet weather
Inventor: TAKAYUKI FUKUNAGA
IPC: B60C11/03
Filed: 2000-10-24
Abstract: The pneumatic tire (10), for high performance automobiles, has a main groove (14) around the circumference at the center of the tread (12) in contact with the ground. At the inner zone of the tread, towards the axially inner side of the tire, the main peripheral and lateral grooves branch from the center groove and, at the axially outer zone, the main peripheral grooves are with angled grooves towards the outer side of the tire, to give an irregular tread structure,  The tire is fitted to give a toe-in of 0.0-0.7 deg  and a camber on a negative range of 0-5 deg . The ground surface area of the tire tread has an outer zone (12L) in three sections, side by side across the tread line. Each section represents one-third of the width of the outer tread zone (12L). The first section, nearest to the center groove (14), has an angle of 55-65 deg , the next section has an angle of 70-80 deg  and the outermost section has an angle of 80-90 deg . The outer tread zone (12L) has a negative pattern repeat of 35-37%, and the inner tread zone (12R) has a negative pattern repeat of 34-39%. The tread structure has a number of lateral grooves, opening from the center groove (14) towards the sides of the tread (12) at an angle to the circumference line. The grooves at the inner zone increase in an angular range of 55-90 deg  at intervals of 45-50 mm in a width of 6-10 mm. Their open ends at the tire side are pref. aligned in the direction of tire forward rotation. A number of tread sculptures (26) are separated by the lateral grooves, each with a number of points where one is pref. positioned in the direction of the forward rotation of the tire (10) in relation to the other points. Each sculpture, next to the center groove (14), has a lateral width of 20-30% of the tread surface contact area at the inner side (12R) of the tread, with a point at an acute angle of 55-70 deg . The outer zone (12L) of the tread has a similar structure to the inner zone, but with a negative pattern repeat of 35-37%, and with a number of angled longitudinal grooves, with an angle of 5-50 deg , increasing in the direction of the tread edge. Each oblique longitudinal groove intersects a number of lateral grooves, with at least three junctions placed at a gap of 9-35% of a width of tread contact surface zone between the center groove (14) and the outer side of the tread and a width of 50-120% of the width of the end of the lateral groove which opens into the center groove (14). The longitudinal and lateral grooves separate sculptured zones (26). Each sculptured zone (26) has a number of points, where one is placed in the direction of forward tire rotation, in relation to the other points. Each sculptured section, next to a main peripheral groove, has a width across the tire (10) of 20-30% of the width of the inner tread zone (12R), and the point is at an acute angle of 55-70 deg . The main lateral grooves are at intervals of 45-50 mm, on the line of the circumference of the tire (10), and have a width of 6-10 mm. The inner tread zone (12R) is divided into two sections, where one is next to the main peripheral groove (14) and extends across two-thirds of the inner tread zone with an angle of 50-70 deg , and the second section covers the remaining one-third of the zone with an angle of 70-90 deg .