Abstract: A tread for a tire includes a plurality of circumferential ribs, at least one of the ribs having sipes extending in a zigzag manner as the sipes extend axially across the rib and also extending in a zigzag manner as the sipes project radially inward from a radially outer surface of the rib.

Abstract: A tread for a pneumatic tire includes central tread elements and shoulder tread elements having leading and trailing tread edges. A pair of circumferentially continuous grooves, one on each half ol the tread, and a plurality of lateral grooves extending from each tread edge toward the center of the tread are provided. The lateral grooves adjacent the central tread elements are curved in shape extending along a line, the line extends toward the center of the tread to form an apex from the center extending outwardly across the tread pattern changing in an opposite direction at an intersection of the circumferential groove along a second line adjacent the shoulder tread element. Shoulder tread elements are arranged in two rows, one row adjacent each lateral edge, the leading edges of the shoulder tread elements being inclined relative to the direction of rotation of the tire.

Abstract: A pneumatic tire 10 having a radially outer tread 12, the tread 12 having a plurality of tread elements defined by grooves arranged circumferentially and laterally around the tread 12 between a pair of lateral tread edges TE to define a tread pattern. The tread 12 has a plurality of tread elements extending across the width of the tread between the lateral edges including central tread elements 24, 26, 28 and shoulder tread elements 20, 22 having leading 21, 25 and trailing tread edges 23, 27. The shoulder tread elements 20, 22 are arranged in two rows SH1, SH2, one row adjacent each lateral edge TE. At least one row of shoulder elements has the leading edges inclined relative to the direction of rotation of the tire 10 having an axially outward portion of the leading edge entering and exiting a footprint contact patch 100 prior to the axially inner portion of the leading edge of the shoulder tread elements 20, 22.

Abstract: The coefficient of friction of an elastomeric sample can be determined by: (a) providing a friction test machine having a rigid wheel with an outer surface defining a curvilinear friction surface, a sample holder and, a force measurement device; (b) placing the elastomeric sample onto the sample holder; (c) adjusting the elastomeric sample and the curvilinear friction surface into frictional engagement thereby forming a curvilinear deformation in the elastomeric sample; (d) rotating the rigid wheel; and, (e) using the force measurement device to obtain a geometry independent measurement indicative of the coefficient of friction of the elastomeric sample.

Abstract: The coefficient of friction of an elastomeric sample can be determined by: (a) providing a friction test machine having a rigid wheel with an outer surface defining a curvilinear friction surface, a sample holder and, a force measurement device; (b) placing the elastomeric sample onto the sample holder; (c) adjusting the elastomeric sample and the curvilinear friction surface into frictional engagement thereby forming a curvilinear deformation in the elastomeric sample; (d) rotating the rigid wheel; and, (e) using the force measurement device to obtain a geometry independent measurement indicative of the coefficient of friction of the elastomeric sample.

Abstract: The loss of tire contact patch area along the tire's inside shoulder, relative to an oval race course, which occurs during chassis roll and lateral deflection, is reduced by providing an asymmetrical molded tire. The tires are defined by an asymmetrical outer tread profile and the tires are mounted on the rear axle of the race vehicle such that the axially outer portion of the asymmetrical tread region of each tire, relative to the race course, has a greater shoulder drop, wherein the shoulder drop is the difference between the maximum radial diameter of the tread measured on the outer tread contour and the diameter of the tread at the tread edge, than the opposing tire shoulder.

Abstract: A pneumatic tire having improved wet traction has lugs containing sipes which change direction within the lug and tie bars in the sipes near each point where the sipes change direction. Siping, and the positioning of tie bars, provide means for minimizing the difference of the principle direction of lug stiffness between individual lugs. Also, a tire of the invention has 4 pitch ratios which are distributed around the tire so that extra large pitches are not located next to small pitches.