Rubber composition and pneumatic tire

A rubber composition comprising at least one diene-based rubber and from 1 to 50 phr of a particulate polyamide having a particle size in a range of from 0.1 to 5 micrometer is disclosed. The particulate polyamide has a melting temperature greater than 200°C as measured by ISO 11357. The particulate polyamide is either (i) at least substantially spherical or has a sphericity ranging from 0.85 to 1, or (ii) has a sphericity of less than 0.8 or ranging from 0.75 to 0.60. Also, a tire comprising such a rubber composition is disclosed.