The design for radial passenger tires was optimized to achieve the most efficient use of a high modulus, high tenacity aramid fiber for belt reinforcement. This required balancing crown angle, belt width, footprint force distribution, and tread squirm to give even wear along with maximum cornering. Additional gains in cornering were demonstrated by using a double tread radius (smaller radius at shoulders) to increase the effectiveness of center ribs in developing lateral force. Improved tire performance resulted from modifying the cord structure to obtain higher belt stiffness.