Winter tyres tyre width 225 mm tyre cross section 55 rim diameter 18 inch load index 109 up to 1030 kg speed rating v up to 149 mph installation all round tyre rolling resistance c wet grip c noise emission 73 db noise classification nc 2 runflat rim protector sipes asymmetrical tread directional tread runflat identification ssr csr sst continental run flat technology ssr self supporting runflat tyre rim protection marking fp mfs