Winter tyres tyre width 255 mm tyre cross section 55 rim diameter 19 inch load index 107 up to 975 kg speed rating v up to 149 mph installation all round tyre rolling resistance f wet grip e noise emission 72 db noise classification nc 2 runflat sipe asymmetrical tread runflat identification ssr csr sst continental run flat technology ssr self supporting runflat tyre