Vredestein ULTRAC is a summer tyre made in total of 49 sizes, ranging from R15 to R15 - this particular dimension is R15, which means it fits to a 15 inch/381mm diameter wheel. This tyre profile of 50 means the sidewall height of the tyre is 50% of the tyre width (175mm), which results in 87.5mm sidewall height. In 175/50 R15, there is only one possible speed index for Vredestein ULTRAC - "", which is good for speeds up to km/h.