Westlake Z-507 is a winter tyre made in total of 65 sizes, ranging from R16 to R16 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 255/40 R18 is 60mm wider than the narrowest dimension (195) and 20mm narrower than the widest one (275). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (255mm), which results in 102mm sidewall height. In
255/40 R18, Z-507 usually competes against
P Zero Winter 2, which is a tyre from
Pirelli with a rating of 88%, compared to 22% of the
Westlake in question.
