The most recognisable Michelin tread pattern, the X, first appeared in 1946. It was the first radial tyre from Michelin and brought with it improved grip, road holding and longevity. First fitted to the Lancia Aurelia, the X was also original equipment on the Citroen Traction Avant and 2CV. There are 13 sizes in the X range. This 185R400 (metric) fits the Traction Avant Big 6.