Tire manufacturers provide recommended tire pressures for the front and rear axles of vehicles, depending on the load and tire size. Changes in these parameters affect the size of the contact area of the tire with the road surface, and consequently the tire operating conditions and vehicle traffic safety.

The article presents the results of testing the deflection of car tires as a function of changes in load and pressure. The tests were carried out using winter tires of three sizes (165/80R14; 195/65R15; 205/55R16) for pressures ranging from 0.1 to 0.3 MPa and loads from 1 to 5 kN. The obtained characteristics of the dependence of the pressure change on the deflection and the length of the trace on the deflection make it possible to determine the area of correct cooperation between the tire and the road surface and to maintain the thermal balance of the tire during the vehicle's motion.