Pneumatic tire comprising a composite reinforcer (R-2) that is self-adhesive by curing to a diene rubber matrix, comprising: one or more reinforcing thread(s) (20), for example a carbon steel cord; covering said thread, individually each thread or collectively several threads, a layer of a thermoplastic polymer composition comprising on the one hand a thermoplastic polymer, the glass transition temperature of which is positive, on the other hand an unsaturated thermoplastic stirene elastomer, the glass transition temperature of which is negative.