Study on the critical speeds of car's movement with low and ultra-low profile tires in a turn

This work proposes an improved algorithm for determining the critical speeds of car's movement with low and ultra-low profile tires in a turn, where sliding of its axles occurs and overturning. The critical speeds are determined by the characteristics of the lateral slipping calculated for their critical normal loading. On the basis of the algorithm an interactive programming system in the MATLAB environment is developed. Graphic dependencies for the radius of the turn are presented, taking into account the slip of the tires with different speeds of a car Honda Civic Aerodeck 1.5iLS with low profile tires of size185/60R14. Results have been obtained on critical speeds against sliding in the front and rear axles and against the car's overturning. Critical speed against overturning are determined in the absence of normal reactions for the inner steered wheels in a turn. The critical speeds of sliding are found to be lower than the overturning, and thus appear to be decisive.