Experimental Investigation of Static Friction Coefficient between Vehicle Tyre and Various Road Conditions

The static friction force increases for an increase in the tangential displacement up to the value that is necessary to initiate gross-sliding of the bodies in contact. The static friction coefficients of tyre tread of different strength properties under varying contact conditions are investigated. Smooth surfaces were considered to evaluate the effects of roughness on adhesion of tyre treads. In this investigation different types of road surfaces were tested. The results show that larger tread contact resulted in higher coefficients of static friction. The static friction coefficient decreased for an increase in the tyre tread stiffness. The static friction coefficient decreased for an increase in the surface roughness, then passes through a minimum and finally increased for higher roughness of the counter face. The effect of contaminants such as water, fuel and lubricant between head and counter face were also investigated.