245/75 R17 doesn't belong to the most popular dimensions for 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 - 75 is height of the tyre, which is calculated as 75% of the tyre width (245mm), which means the sidewall height has 183.75 mm. The wheel diameter is R17, which means it fits to a 17 inch/431.8mm diameter wheel. The total circumference of the tyre is mm, which is very similar to 185/60 R15(1894.38 mm), 255/50 R20(2397.04 mm), 190/50 R17(1953.44 mm), 255/70 R15(2318.5 mm), 195/55 R16(1950.61 mm), 265/35 R19(2098.9 mm), 195/70 R14(1974.81 mm).