Michelin Pilot Sport CUP 2 is a summer tyre made in total of 130 sizes, ranging from R17 to R17 - this particular dimension is R20, which means it fits to a 20 inch/508mm diameter wheel. 345/30 R20 is 130mm wider than the narrowest dimension (215) and -20mm narrower than the widest one (325). This tyre profile of 30 means the sidewall height of the tyre is 30% of the tyre width (345mm), which results in 103.5mm sidewall height. In 345/30 R20, there is only one possible speed index for Michelin Pilot Sport CUP 2 - "Y", which is good for speeds up to 300 km/h.