Gravelking is designed for hard and fast surfaces. ZSG Natural Compound technology, which is made up of a softer compound that is overlaid on the outside with a harder compound for increased durability. AX-Alphacord technology uses the highest density, flattest fibers possible for flexibility, lightness and increased puncture resistance. This durability is further enhanced by the Anti FlatCasing coating across the entire surface of the tire, which again increases puncture protection.