TWO-WHEELED VEHICLE TIRE
FIG1 illustrates a cross-sectional view of a two-wheeled vehicle tire in accordance with an embodiment of the disclosure
FIG1 illustrates a cross-sectional view of a two-wheeled vehicle tire (hereinafter, simply referred to as "tire") 1 in accordance with an embodiment of the disclosure, wherein the tire is placed under a standard condition. As illustrated in FIG1, the tire 1 according to the embodiment includes a carcass 6 extending between axially spaced bead cores 5 each disposed in a respective one of bead portions 4 through a tread portion 2 and sidewall portions 3, and a bead apex rubber 8 extending radially outwardly from each bead core 5. Note that in FIG1 the right half portion of the tire 1 is omitted since it has a substantially symmetrical structure as the left half portion. As illustrated in FIG1, the tread portion 2 according to the embodiment includes rows of circumferentially arranged crown blocks 9, middle blocks 10, and shoulder blocks 11. Preferably, the tread portion 2 has a land ratio ranging from 14% to 35%. Such a tread portion 2 may be suitable for traveling on rough terrain, e.g., off-road bike competitions. Bias tires for off-road bike having a basic structure as shown in FIG1 were prototyped based on the specification in Table 1. As a comparative example tire (Ref. 1), a tire for off-road bike having a pair of bead apex rubbers which are made of one kind of rubber was prototyped. Then, each test tire was installed to a motorcycle as a rear wheel to test.
cross-sectional view
8
bead apex rubber
11
shoulder blocks shoulder block
9
crown blocks
2
tread portion
10
middle blocks
3
sidewall portions sidewall portion
['1. A two-wheeled vehicle tire (1) comprising: a carcass (6) extending between bead cores (5) each disposed in a respective one of bead portions (4) through a tread portion (2) and sidewall portions (3), the carcass (6) comprising at least one carcass ply (6A) having a ply main portion (6a) extending between the bead cores (5) through the tread portion (2); and a bead apex rubber (8) extending radially outwardly from each bead core (5), wherein the bead apex rubber (8) comprises a first rubber portion (8A) arranged adjacent to the ply main portion (6a), and a second rubber portion (8B) arranged axially outwardly of the first rubber portion (8A), the first rubber portion (8A) has a first end (8a) positioning radially outermost thereof, the second rubber portion (8B) has a second end (8b) positioning radially outermost thereof, and the first end (8a) is located radially outwardly of the second end (8b), and  characterized in that a substantially constant-thickness region (R1) of the first rubber portion (8A) in which a difference between a maximum thickness (t1) and a minimum thickness (t2) is equal to or less than 20% of the minimum thickness (t2) has a length equal to or more than 80% of a radial height (h1) of the first rubber portion (8A) from the bead core (5) to the first end (8a).', '7. The two-wheeled vehicle tire (1) according to any one of claims 1 to 6, the tread portion (2) further comprising a row of shoulder blocks (11) arranged in a tire circumferential direction to define a tread edge (Te), each shoulder block (11) connected to one of the sidewall portions (3) at a boundary location (3a), and the first end (8a) being located radially outwardly of the boundary location (3a).']