Kumho Ecsta PS91 is a summer tyre made in total of 48 sizes, ranging from R18 to R18 - this particular dimension is R19, which means it fits to a 19 inch/482.6mm diameter wheel. 305/30 R19 is 80mm wider than the narrowest dimension (225) and -30mm narrower than the widest one (275). This tyre profile of 30 means the sidewall height of the tyre is 30% of the tyre width (305mm), which results in 91.5mm sidewall height. In 305/30 R19, there is only one possible speed index for Kumho Ecsta PS91 - "Y", which is good for speeds up to 300 km/h. In 305/30 R19, Ecsta PS91 usually competes against Advan Sport V105, which is a tyre from Yokohama with a rating of 0%, compared to 16% of the Kumho in question.