Kumho Ecsta HS52 is a summer tyre made in total of 88 sizes, ranging from R14 to R14 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 225/55 R18 is 50mm wider than the narrowest dimension (175) and 20mm narrower than the widest one (245). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (225mm), which results in 123.75mm sidewall height. In 225/55 R18, there is only one possible speed index for Kumho Ecsta HS52 - "W", which is good for speeds up to 270 km/h. In 225/55 R18, Ecsta HS52 usually competes against Dynaxer HP4, which is a tyre from Kleber with a rating of 76%, compared to 78% of the Kumho in question.