Royal Black Royalwinter UHP is a winter tyre made in total of 37 sizes, ranging from R16 to R16 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 225/40 R18 is 10mm wider than the narrowest dimension (215) and 50mm narrower than the widest one (275). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (225mm), which results in 90mm sidewall height. In
225/40 R18, Black winter UHP usually competes against
Snowpower UHP, which is a tyre from
Tristar with a rating of 0%, compared to 16% of the
Royal in question.
Winter
