Metzeler Roadtec Z8 Interact is a winter tyre made in total of 22 sizes, ranging from R17 to R17 - this particular dimension is R17, which means it fits to a 17 inch/431.8mm diameter wheel. 180/55 R17 is 70mm wider than the narrowest dimension (110) and -20mm narrower than the widest one (160). This tyre profile of 55 means the sidewall height of the tyre is 55% of the tyre width (180mm), which results in 99mm sidewall height. In 180/55 R17, there is only one possible speed index for Metzeler Roadtec Z8 Interact - "W", which is good for speeds up to 270 km/h.
