Avon ZZ5 is a summer tyre made in total of 18 sizes, ranging from R17 to R17 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 245/45 R18 is 40mm wider than the narrowest dimension (205) and 10mm narrower than the widest one (255). This tyre profile of 45 means the sidewall height of the tyre is 45% of the tyre width (245mm), which results in 110.25mm sidewall height. In 245/45 R18, there is only one possible speed index for Avon ZZ5 - "Y", which is good for speeds up to 300 km/h. In 245/45 R18, ZZ5 usually competes against Pilot Sport 4, which is a tyre from Michelin with a rating of 84%, compared to 0% of the Avon in question.