Avon ZV7 is a summer tyre made in total of 278 sizes, ranging from R13 to R13 - this particular dimension is R15, which means it fits to a 15 inch/381mm diameter wheel. 185/55 R15 is 35mm wider than the narrowest dimension (150) and 90mm narrower than the widest one (275). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (185mm), which results in 101.75mm sidewall height. In 185/55 R15, there are 3 possible speed indexes for Avon ZV7 - "V","T","H", which are good for speeds up to 240, 190, 210 km/h. In 185/55 R15, ZV7 usually competes against N blue HD Plus, which is a tyre from Nexen with a rating of 0%, compared to 17% of the Avon in question.