155/60 R15 doesn't belong to the most popular dimensions for all-tests tyres - there are tyre models available, which can be compared to
325/30 R21,
155/65 R13,
155/65 R14. Let's break down the sizing - 60 is height of the tyre, which is calculated as 60% of the tyre width (155mm), which means the sidewall height has 93 mm. The wheel diameter is R15, which means it fits to a 15 inch/381mm diameter wheel. The total circumference of the tyre is mm, which is very similar to 205/70 R15
(2098.58 mm), 275/40 R20
(2287.08 mm), 215/45 R17
(1964.44 mm), 275/55 R17
(2306.87 mm), 215/60 R17
(2167.07 mm), 285/30 R21
(2212.94 mm), 215/80 R15
(2277.65 mm).