Method of retreading tires

A method of retreading tires, comprising, in combination, the first step of positioning a tread strip in proximity to the outer periphery of a tire carcass;

• the second step of providing intermediate said carcass and said strip an unvulcanized adhesive bonding layer;
• the third step of effecting temporary adhesive bonding of said strip to said carcass by pressing said strip and said carcass together with a pressure sufficient to cause the material of said bonding layer to enter into and completely fill all the surface depressions in the facing surfaces of said strip and of said carcass and to completely fill the space intermediate the facing surfaces of said strip and of said carcass;
• and the fourth step of effecting permanent bonding of said tread strip to said carcass by effecting vulcanization of said bonding layer by heating, including effecting vulcanization of the marginal portions of said layer in advance of vulcanization of the central portion of said layer by providing intermediate said tread strip and said carcass a greater amount of vulcanization accelerator in the region of said marginal portions than in the region of said central portion and then heating the tire, so that the decrease in adhesive force of said central portion resulting during heating of the latter is delayed until after the vulcanization of said marginal portions has been substantially completed, whereby during the course of the vulcanization of the entire bonding layer the total adhesive force exerted by said layer will be sufficient to hold said tread strip in place on said carcass without the need for a holding wrapper or holding form.