Bridgestone Weather Control A005 is a allround tyre made in total of 86 sizes, ranging from R15 to R19 - this particular dimension is R18, which means it fits to a 18 inch/457.2mm diameter wheel. 245/40 R18 is 70mm wider than the narrowest dimension (175) and 30mm narrower than the widest one (275). This tyre profile of 40 means the sidewall height of the tyre is 40% of the tyre width (245mm), which results in 98mm sidewall height. In 245/40 R18, there is only one possible speed index for Bridgestone Weather Control A005 - "Y", which is good for speeds up to 300 km/h. In 245/40 R18, Weather Control A005 usually competes against AllSeasonContact, which is a tyre from Continental with a rating of 88%, compared to 67% of the Bridgestone in question.