Nexen N Fera Primus is a summer tyre made in total of 40 sizes, ranging from R15 to R15 - this particular dimension is R16, which means it fits to a 16 inch/406.4mm diameter wheel. 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 R16, there is only one possible speed index for Nexen N Fera Primus - "V", which is good for speeds up to 240 km/h.