Yokohama BluEarth-4S AW21 is a allround tyre made in total of 40 sizes, ranging from R14 to R14 - this particular dimension is R19, which means it fits to a 19 inch/482.6mm diameter wheel. 245/40 R19 is 70mm wider than the narrowest dimension (175) and -30mm narrower than the widest one (215). 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 R19, there is only one possible speed index for Yokohama BluEarth-4S AW21 - "Y", which is good for speeds up to 300 km/h.