Pirelli Scorpion Winter is a winter tyre made in total of 213 sizes, ranging from R16 to R16 - this particular dimension is R21, which means it fits to a 21 inch/533.4mm diameter wheel. 275/50 R21 is 60mm wider than the narrowest dimension (215) and 50mm narrower than the widest one (325). This tyre profile of 50 means the sidewall height of the tyre is 50% of the tyre width (275mm), which results in 137.5mm sidewall height. In 275/50 R21, there is only one possible speed index for Pirelli Scorpion Winter - "V", which is good for speeds up to 240 km/h. In 275/50 R21, Scorpion Winter usually competes against Pilot Alpin 5 SUV, which is a tyre from Michelin with a rating of %, compared to 0% of the Pirelli in question.