The Influence of Run-Flat Tires on the Ride Comfort and Dynamic Behavior of the Vehicle

Run-flat tires improve vehicle safety by maintaining mobility under air pressure loss, yet their higher vertical stiffness is widely perceived to reduce ride comfort. This work proposes a simulation-based approach for assessing the impact of tire construction, size, and inflation pressure on vertical comfort using standardized random road excitations and frequency-weighted acceleration metrics. Vehicle vertical dynamics were captured using a two-degree-of-freedom quarter-vehicle formulation, built in MATLAB/Simulink and driven by stochastic road inputs representative of typical paved surfaces and realistic driving conditions. The vertical acceleration of the sprung mass was evaluated through an ISO-compliant frequency-weighting filter, enabling a comfort assessment directly linked to whole-body vibration criteria. Simulations over multiple tires and operating configurations showed that run-flat tires consistently produce higher weighted acceleration levels than conventional tires at matched conditions, and that increased inflation pressure further amplifies this comfort deficit. The results provided a quantitative characterization of the impact of run-flat technology on ride comfort and highlight the key role of tire-related parameters in shaping the vertical vibration environment experienced by vehicle occupants. All results are reported at the tire-suspension-sprung mass subsystem level and should be interpreted as indicative comparative benchmarks rather than absolute occupant comfort predictions. These insights can further inform the development of vibration-based monitoring strategies for tire and suspension performance.