Falken Azenis FK520 is a summer tyre made in total of 115 sizes, ranging from R17 to R17 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 245/40 R18 is 40mm wider than the narrowest dimension (205) and 80mm narrower than the widest one (325). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (245mm), which results in 98mm sidewall height. In 245/40 R18, there is only one possible speed index for Falken Azenis FK520 - "Y", which is good for speeds up to 300 km/h. In 245/40 R18, Azenis FK520 usually competes against Victra Sport 5, which is a tyre from Maxxis with a rating of 69%, compared to 75% of the Falken in question.