Abstract: A tire testing apparatus performs the test by rotating a tire while the tire is in contact with a drum. A plurality of sensors are provided on the outer circumferential surface of the drum and are arranged side by side along a widthwise direction of the drum, thereby measuring the ground contact forces at the ground contact position with the tire. A calculation unit obtains, based on the ground contact forces measured by the sensors, a displacement amount Dy of the ground contact position in the widthwise direction and a change amount ?Fy of the ground contact force Fy in the widthwise direction which corresponds to the displacement amount Dy, thereby calculating the lateral stiffness sharing rate Ky rib on the basis of the displacement amount Dy and the change amount ?Fy.

Abstract: A tire testing apparatus performs the test by rotating a tire while the tire is in contact with a drum. A plurality of sensors are provided on the outer circumferential surface of the drum and are arranged side by side along a widthwise direction of the drum, thereby measuring the ground contact forces at the ground contact position with the tire. A calculation unit obtains, based on the ground contact forces measured by the sensors, a displacement amount Dy of the ground contact position in the widthwise direction and a change amount ?Fy of the ground contact force Fy in the widthwise direction which corresponds to the displacement amount Dy, thereby calculating the lateral stiffness sharing rate Ky rib on the basis of the displacement amount Dy and the change amount ?Fy.