VENTUS SR20 (SR20) VENTUS SR20 (SR20) Rally/Snow Directional snow rally tire for well balanced maximum grip on snow, wet and dry surface, specially for Monte-Carlo rally use. Sizes & Specs Size Compound Rim Size Overall Diameter (mm) Section Width (mm) Tread Width (mm) Permitted Optimum 200/650R18 C5 7.5 8.5 648 224 200