145/70 R12 doesn't belong to the most popular dimensions for allround tyres - there are tyre models available, which can be compared to
325/30 R21,
155/60 R15,
155/65 R13. Let's break down the sizing - 70 is height of the tyre, which is calculated as 70% of the tyre width (145mm), which means the sidewall height has 101.5 mm. The wheel diameter is R12, which means it fits to a 12 inch/304.8mm diameter wheel. The total circumference of the tyre is mm, which is very similar to 205/55 R16
(1985.17 mm), 275/30 R21
(2194.09 mm), 205/75 R16
(2242.78 mm), 275/40 R21
(2366.88 mm), 215/45 R18
(2044.23 mm), 275/55 R19
(2466.46 mm), 215/65 R15
(2075.02 mm).
