The net velocity of any point on the wheel is the vector sum of the constant translational velocity, and the rotational velocity.

Because the magnitudes of these two velocities are equal on the circumference, the net velocity for key points on the wheel are:

top of the wheel:        v + v = 2v
center of the wheel:    v + 0 = v
bottom of the wheel:   v - v = 0

The bottom of the wheel is instantaneously at rest! There is no slipping where the rubber meets the road.