Michelin XZX | Michelin XZX Tires Michelin XZX radial is available for many popular European applications requiring a 12 inch radial tire and authentic styling. These 15 inch radial tires feature Michelin's XZX tread pattern and an S speed rating. With radial casing plies, Michelin XZX Tires offered a considerable advance in technology. Its revolutionary construction for the time had the special feature of separating the sidewall function from the crown function. The first major innovation from Michelin, the radial tire was first marketed as the "X" tire in 1949. At that time, Lancia was the first car manufacturer to fit the X tire as original equipment on the Aurelia model. From 1955, radial technology became more popular and the majority of European car manufacturers opted for the radial solution. The X could be fitted to cars of very different categories, from the original and popular 2 CV or Beetle to the fascinating Mercedes 190SL or Facel Vega. The advantages of the radial tire compared with the cross-ply tire could be clearly seen in all areas :?- greater safety (road-holding, grip, braking)?- economical to use (double the mileage, considerable reduction in fuel consumption) - increased comfort thanks to the flexibility of the sidewalls. In the Fifties, the superiority of the X tire was such that a number of racing drivers adopted it, although Michelin was not officially involved in any racing.