Toyo Proxes T1R is a summer tyre made in total of 21 sizes, ranging from R14 to R14 - this particular dimension is R22, which means it fits to a 22 inch/558.8mm diameter wheel. 255/30 R22 is 30mm wider than the narrowest dimension (225) and 40mm narrower than the widest one (295). This tyre profile of 30 means the sidewall height of the tyre is 30% of the tyre width (255mm), which results in 76.5mm sidewall height. In 255/30 R22, there is only one possible speed index for Toyo Proxes T1R - "Y", which is good for speeds up to 300 km/h.