This diagram shows a BFGoodrich Radial Mud-Terrain T/A KM2. Notice that the internal steel cords go side-to-side from one bead to the other. This cord orientation allows the tire casing to flex more easily. Radial construction doesn't "fight" itself as the tire flexes, so a radial tire runs cooler. Since a radial flexes more easily, it is more adept at absorbing small bumps and conforming to jagged off-road surfaces. Extra plies are added across the top (or "crown") of the tire to increase puncture resistance. The radial tire's internal construction costs more to produce than a bias ply, so a radial costs more at the counter.