Firestone Winterhawk 4 is a winter tyre made in total of 100 sizes, ranging from R14 to R14 - this particular dimension is R14, which means it fits to a 14 inch/355.6mm diameter wheel. This tyre profile of 65 means the sidewall height of the tyre is 65% of the tyre width (155mm), which results in 100.75mm sidewall height. In 155/65 R14, there is only one possible speed index for Firestone Winterhawk 4 - "T", which is good for speeds up to 190 km/h. In 155/65 R14, Winterhawk 4 usually competes against WR D4, which is a tyre from Nokian with a rating of 54%, compared to 69% of the Firestone in question.