Firestone TZ300a is a summer tyre made in total of 13 sizes, ranging from R15 to R15 - this particular dimension is R15, which means it fits to a 15 inch/381mm diameter wheel. 205/60 R15 is 30mm wider than the narrowest dimension (175) and -10mm narrower than the widest one (195). This tyre profile of 60 means the sidewall height of the tyre is 60% of the tyre width (205mm), which results in 123mm sidewall height. In 205/60 R15, there are 2 possible speed indexes for Firestone TZ300a - "H","V", which are good for speeds up to 210, 240 km/h.