The cornering property is a key factor for the driveability of automobile vehicles. In order to design automobile vehicles capable of achieving higher driveability, it is important to evaluate the cornering property of the automobile vehicle accurately. For an automobile vehicle provided with wheels to which tires are mounted, various factors are involved in its cornering property, including vehicle structure properties (e.g., weight, balance), suspension properties, tire properties, and road surface conditions. When an automobile vehicle is cornering, an equilibrium state is maintained between the sum of the forces (cornering forces) towards the center of the cornering line generated on the contact surfaces of the front and rear tires, and the centrifugal force of the vehicle. The magnitude of the cornering force varies depending on the types of automobile vehicles, the tires, or the traveling conditions. In order to evaluate the cornering property of automobile vehicles, it is significantly important to compare and evaluate the cornering forces under various traveling conditions.
As an example of methods of evaluating the cornering force generated in a specific tire, a method that uses known indoor cornering test devices has been described. In the description of the indoor cornering test devices, for example, a specific tire is made in contact with a simulated road surface with the specific tire being loaded. Then, the specific tire is rotated while moving the virtual road surface and the rotation axis of the specific tire relatively to each other, and the magnitude of the cornering force generated on the contact surface of the specific tire is measured. However, a cornering force generated in a tire of a vehicle is affected by various factors such as vehicle structure properties (e.g., weight balance), suspension properties, tire properties, and road surface conditions as described above. Moreover, during actual traveling of the vehicle, changes in the load applied to the wheel occur more frequently due to changes in, such as, postures of the vehicle. Thus, known indoor cornering test devices have had a limitation in accuracy in reproducing various conditions that the vehicle may encounter after actual mounting of the tire thereon and during actual traveling on the road surface (e.g., condition of load applied to the tire, tire rotating condition). Thus, with such indoor cornering test devices, when a specific tire is actually mounted to a vehicle, accurate measurement of the cornering force generated on a contact surface of the specific tire cannot be determined. On the other hand, as a method of evaluating a cornering force generated in a tire actually mounted to a vehicle, Patent Document 1 describes a system for predicting forces generated in a tire in which a sensor is used to measure a torsional deformation of the side wall of the tire, and a cornering force that may be generated in the tire is estimated based on the measured torsional deformation.
Patent Document 1: JP 2004-512207 A