The paper presents a comprehensive study of feasibility and effectiveness of using solid carbon residue (pyrolysate), obtained through the low-temperature pyrolysis of worn car tyres, as a functional filler in rubber compound formulations based on butadiene nitrile rubbers (BNK) of the BNKS-18AMN and BNKS-28AMN grades. The issues of polymer waste disposal and search for cost-effective alternatives to traditional grades of carbon black produced from fossil raw materials provide the relevance of the research. It examines the physicochemical properties of pyrolytic carbon, including its particle size distribution and surface activity. Using vibroreometry (MDR-2000), equilibrium swelling, and physical-mechanical testing, a comparative analysis was conducted of the vulcanization kinetics and properties of vulcanisates containing pyrolysate, compared with reference compounds filled with P 803 carbon black, kaolin, and chalk. Pyrolysate specific surface chemistry and high ash content (including zinc oxide and sulphides) affect significantly on the induction period and the rate of vulcanisation, acting as a filler and as a secondary activator of the cross-linking process. Therefore, the optimisation of dispersion and vulcanising group provide an effective replacement of low activity fillers and partially replace semi-active carbon black without any significant deterioration in the performance characteristics of the rubbers. The research offers prospects for the development of resource-saving technologies in the manufacture of rubber products.