Pneumatic tire for a motorcycle

A pneumatic tire for a motorcycle comprising:

• a carcass extending between a pair of bead cores,
• a tread reinforcing cord layer arranged outside the carcass in a tire radial direction,
• a tread rubber arranged radially outside the tread reinforcing cord layer, the tread rubber forming a ground contacting surface including a crown ground contacting surface for contacting with the ground during straight running, and a pair of shoulder ground contacting surfaces for contacting with the ground during cornering, and
• a pair of sidewall portions extending inwardly in the tire radial direction from the tread rubber, a portion of each of the pair of sidewall portions being arranged between the tread reinforcing cord layer and the tread rubber in a tire axial direction,
• wherein
• the tread rubber comprises a base rubber layer and a pair of shoulder rubber layers,
• the base rubber layer comprises a cover portion covering at least the tread reinforcing cord layer over an entire width thereof and a convex portion protruding radially outwardly from the cover portion so as to form the crown ground contacting surface,
• a width, in the tire axial direction, of the convex portion in the ground contacting surface is in a range of from 0.1 to 0.4 times a tread width, and a thickness of the cover portion that extends from the convex portion to tread edges is consistently smaller than a thickness of the pair of shoulder rubber layers,
• the shoulder rubber layers are arranged radially outside the cover portion so as to form the shoulder ground contacting surfaces,
• the base rubber layer is made of a first rubber composition, a hardness of the first rubber composition being larger than a hardness of the shoulder rubber layers,
• the shoulder rubber layers are made of a second rubber composition, an amount of oil component contained in the second rubber composition being larger than an amount of oil component contained in the base rubber layer,
• the amount of oil component in the second rubber composition is larger by 1 to 10 parts by mass than an amount of oil component in the first rubber composition with respect to 100 parts by mass of a rubber component,
• the hardness of the first rubber composition is in a range of from 58 to 70 degrees,
• a hardness of the second rubber composition is in a range of from 53 to 68 degrees,
• the hardness of the first rubber composition is larger than the hardness of the second rubber composition by 2 to 8 degrees, and
• the tread width is a distance between the tread edges in the tire axial direction and is a maximum width of the tire.

A pneumatic tire for a motorcycle comprising:

• a carcass extending between a pair of bead cores,
• a tread reinforcing cord layer arranged outside the carcass in a tire radial direction,
• a tread rubber arranged radially outside the tread reinforcing cord layer, the tread rubber forming a ground contacting surface including a crown ground contacting surface for contacting with the ground during straight running, and a pair of shoulder ground contacting surfaces for contacting with the ground during cornering, and
• a pair of sidewall portions extending inwardly in the tire radial direction from the tread rubber, a portion of each of the pair of sidewall portions being arranged between the tread reinforcing cord layer and the tread rubber in a tire axial direction,
• wherein
• the tread rubber comprises a base rubber layer and a pair of shoulder rubber layers,
• the base rubber layer comprises a cover portion covering at least the tread reinforcing cord layer over an entire width thereof and a convex portion protruding radially outwardly from the cover portion so as to form the crown ground contacting surface,
• a width, in the tire axial direction, of the convex portion in the ground contacting surface is in a range of from 0.1 to 0.4 times a tread width, and a thickness of the cover portion that extends from the convex portion to tread edges is consistently smaller than a thickness of the pair of shoulder rubber layers,
• the shoulder rubber layers are arranged radially outside the cover portion so as to form the shoulder ground contacting surfaces,
• the base rubber layer is made of a first rubber composition, a hardness of the first rubber composition being larger than a hardness of the shoulder rubber layers,
• the shoulder rubber layers are made of a second rubber composition, an amount of oil component contained in the second rubber composition being larger than an amount of oil component contained in the base rubber layer,
• the amount of oil component in the second rubber composition is larger by 1 to 10 parts by mass than an amount of oil component in the first rubber composition with respect to 100 parts by mass of a rubber component, and
• a maximum rubber thickness of the base rubber layer is in a range of from 1.1 to 1.4 times a maximum rubber thickness of the shoulder rubber layers.