The present invention is a rubber composition comprising microencapsulated sulfur and free sulfur. The composition is particularly useful as a cushion gum in retreading procedures. In one embodiment of the invention, the composition further comprises one or more ultra-accelerator curing agents for rubber. In another embodiment of the invention, the rubber composition has a t.sub.90 within twenty percent, more preferably within ten percent, and more preferably within five percent of the unaged green rubber composition, after 28 days aging at forty degrees Celsius. In another embodiment of the invention, the rubber composition has a t.sub.0 within twenty percent, more preferably within ten percent, and more preferably within five percent of the unaged green rubber composition, after 28 days aging at forty degrees Celsius. In another embodiment of the invention, approximately between forty and fifteen percent, more preferably between thirty and twenty percent, and more preferably approximately twenty-five percent by weight of the sulfur in the composition is encapsulated.Another embodiment of the invention is a tire comprising the rubber composition of the invention. Another embodiment of the invention is a recapped or repaired tire comprising the rubber composition of the invention. A further embodiment of the invention is a method of retreading a tire comprising application of the rubber composition of the invention between the tire tread and the carcass of a tire. A further embodiment of the invention comprises a method of repairing a tire comprising application of the rubber composition of the invention to a defect in the tire. A further embodiment comprises repair of rubber articles using the composition.