Patent ID: 7469578

Claim:
A method of evaluating a cornering stability of a wheel that is mounted to a vehicle and has a tire assembled thereto, when the vehicle is cornering on a road surface, the method comprising: a deriving step of deriving a cumulative value of lateral displacement at a predetermined portion of the tire due to lateral deformation of an outer circumference surface portion of the tire when the vehicle is cornering, the cumulative value representing a resultant of an accumulation of the lateral displacement from a contact leading edge to a contact trailing edge of the tire, and the cumulative value of displacement being derived continually at every unit of time; a first calculating step of repeatedly calculating, each time when the cumulative value of displacement is derived, a change amount in the cumulative value of displacement for the unit of time as a change ratio in tire deformation by using the cumulative value of displacement derived present time and the cumulative value of displacement derived last time; a second calculating step of calculating, each time when the change ratio is calculated, a rate of change ratio in tire deformation, the rate of change ratio being calculated using the change ratio in tire deformation previously calculated as a reference value and the change ratio calculated present time; and a determining step of determining, based on the rate of change ratio calculated in the second calculating step, a cornering stability of the wheel that represents a degree of a margin in which the wheel keeps no sliding and beyond which the wheel start sliding.