A two-dimensional transient pyrolysis model for a large tire particle has been developed. The model considers both transportation and kinetics phenomena. The high content of volatile matters (VM) and the large size of the tire particle sample make the proposed approach different from other pyrolysis models. One novel contribution is the modelling of the transportation of the pyrolysis products by a simplified "bubbling" mechanism and the quantitative description of the thermal and kinetic changes which occur during the pyrolysis process. The model was tested with independent experimental data and a good agreement was found.