Pneumatic tire

1. A run-flat tire comprising a plurality of radial protrusions each extending in a tire radial direction on a tire surface and having a shape protruding from the tire surface outward in a tire width direction, wherein

the plurality of radial protrusions are provided radially with a tire rotation axis as a center,

the plurality of radial protrusions each have an outer end portion being an end portion located on an outer side in the tire radial direction and an inner end portion that continues smoothly into a rim guard, and

the outer end portion is provided to the tire surface in a tire maximum width portion in the tire width direction,

wherein a width of the tire maximum width portion measured in the tire radial direction is within a range of 10 mm on each of outer and inner sides, in the tire radial direction, of a tire maximum width point, and

wherein the plurality of radial protrusions have a relation of 1.0≦p/h≦50.0 and 1.0 ≦(p-w)/w≦100.0, where “h” is a maximum height of each radial protrusion measured in the tire width direction, “w” is a width of each radial protrusion measured in a direction perpendicular to the tire radial direction, and “p” is a pitch between the adjacent radial protrusions,

the rim guard extending along a circumference which has the tire rotation axis as a center, and protruding outwardly in the tire width direction arranged on an exterior surface of a bead portion included in the tire, for the purpose of preventing at least one of the tire and a rim from being damaged due to a contact with obstacles,

an inner end portion of the rim guard, located on an inner side in the tire radial direction, continues smoothly into the exterior surface of the bead portion

wherein a smooth surface is formed over an entire area between each of the adjacent radial protrusions on the tire surface.

2. The run-flat tire according to claim 1 , further comprising a circular circumferential protrusion extending along a circumference which has the tire rotation axis as a center and having a shape protruding outward in the tire width direction, wherein

the circular circumferential protrusion is provided in the tire maximum width portion.

3. The run-flat tire according to claim 2 , wherein a height of the circular circumferential protrusion measured in the tire width direction is 0.2 times to 1.5 times, both inclusive, of a maximum height of each of the plurality of radial protrusions measured in the tire width direction.

4. The run-flat tire according to claim 2 , wherein a width of the circular circumferential protrusion measured in the tire radial direction is 2 mm to 22 mm, both inclusive.

5. The run-flat tire according to claim 1 , wherein

the outer end portion has an end face on the outer side in the tire radial direction, and

the end face forms an angle larger than 0° but not exceeding 90° with respect to the tire surface.

6. The run-flat tire according to claim 1 , wherein a height of the outer end portion measured in the tire width direction decreases toward the outer side in the tire radial direction.

7. The run-flat tire according to claim 1 , wherein the plurality of radial protrusions have a relation of 2.0≦p/h≦24.0 and 4.0≦(p-w)/w≦39.0.

8. The run-flat tire according to claim 7 , wherein the plurality of radial protrusions have a relation of 10.0≦p/h≦20.0 and 4.0≦(p-w)/w≦39.0.

9. The run-flat tire according to claim 1 , wherein the radial protrusions are formed with a constant pitch in a tire circumferential direction.

10. The run-flat tire according to claim 1 , wherein all the radial protrusions extend in a same direction with respect to the tire radial direction.