Apollo Aspire XP Winter is a winter tyre made in total of 20 sizes, ranging from R16 to R16 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 235/55 R18 is 20mm wider than the narrowest dimension (215) and 10mm narrower than the widest one (245). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (235mm), which results in 129.25mm sidewall height. In 235/55 R18, Aspire XP Winter usually competes against I FIT LW31, which is a tyre from Laufenn with a rating of 51%, compared to 50% of the Apollo in question.