Rubber composition and tire

A rubber composition comprising at least one diene based elastomer; an α,ω-bis(N,N'-dihydrocarbylthiocarbamamoyldithio)alkane; and sulfur in a form selected from the group consisting of elemental sulfur and insoluble sulfur is disclosed. The rubber composition is essentially free of cure accelerators. Also, a pneumatic tire (1) comprising such a rubber composition is disclosed. In one aspect, the tire (1) is a runflat tire comprising a sidewall insert (12), wherein the sidewall insert (12) comprises said rubber composition.