Abstract <p>In this study, porous hollow cylinders based on β-SiAlON were produced via self-propagating high-temperature synthesis (SHS). The synthesis process involved two stages: (1) the preliminary structuring of a powder mixture of silicon, aluminum, and microsilica, with the incorporation of reinforcing basalt fibers into the porous reactive blanks, and (2) the nitridation of these blanks through SHS. The investigation examined the effect of the cylinder inner diameter on nitrogen content, burning velocity, maximum combustion temperature, porosity, gas permeability, compressive strength, and the phase composition of the products. The microstructure of the combustion products was also analyzed. For reaction blanks with an outer diameter of 90 mm, the combustion reaction could be initiated when the inner diameter was 50 mm or less. The porosity of the resulting β-SiAlON-based materials ranged from 49.5 to 51.8%, predominantly featuring open-type gas-permeable pores. Single-phase hollow cylinders were obtained using reaction blanks with the inner diameter of 20 mm or less. Increasing the inner diameter beyond 20 mm led to incomplete nitridation, as indicated by the multiphase composition of the resulting combustion products. As the inner diameter increased, the compressive strength of the combustion products decreased from 1.35 to 0.25 MPa.</p>