The Jetko "Positive" is great on grooved, hard-packed clay, medium moisture. The angled lines sticking into the sidewall off of the solid line around that help with side bite and structure. The two square pins in each outer trapezoid shape and the two small bars inside each of the inner trapezoids to helps when the tire is driven out of the groove. The vertical bars that are in each inner trapezoid to increase tire life from tire expansion in the middle.