The width is increased, but the friction is decreased! The sine wave design provides three lips per wheel for superior lateral grip. When you want to slide, they break away smoothly and recover easily.
The wave pattern design allows for a thin contact patch touching the ground and therefore less friction, resulting in a quicker ride.
The alternating pattern of grooves significantly reduces hydroplaning by channeling liquid, sand or gravel out and away from the surface of the wheel, allowing for a firm contact patch with the ground.