The same critical lateral slip used in the Fy calculation is also used in determining the condition of the tire.  If the lateral slip angle is less than the critical lateral slip, the tire is in elastic deformation state.  In that case, the aligning torque is computed as follows:

In the case where the lateral slip angle is greater than the Alpha Critical, the tire is in a complete sliding state and the aligning torque is:

See Also:

Longitudinal Force

Lateral Force

Vertical Force

Rolling Resistance Moment