Kumho Ecsta PS91 is a summer tyre made in total of 48 sizes, ranging from R18 to R18 - this particular dimension is R17, which means it fits to a 17 inch/431.8mm diameter wheel. This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (215mm), which results in 86mm sidewall height. In 215/40 R17, Ecsta PS91 usually competes against Advan Sport V105, which is a tyre from Yokohama with a rating of 0%, compared to 21% of the Kumho in question.