Yokohama Advan Sport V105 is a summer tyre made in total of 122 sizes, ranging from R16 to R16 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 255/40 R18 is 60mm wider than the narrowest dimension (195) and 50mm narrower than the widest one (305). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (255mm), which results in 102mm sidewall height. In 255/40 R18, there is only one possible speed index for Yokohama Advan Sport V105 - "Y", which is good for speeds up to 300 km/h. In 255/40 R18, Advan Sport V105 usually competes against Ecsta PS71, which is a tyre from Kumho with a rating of 77%, compared to 39% of the Yokohama in question.