255/30 R22 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 - 30 is height of the tyre, which is calculated as 30% of the tyre width (255mm), which means the sidewall height has 76.5 mm. The wheel diameter is R22, which means it fits to a 22 inch/558.8mm diameter wheel. The total circumference of the tyre is mm, which is very similar to 235/55 R19(2328.23 mm), 235/70 R16(2310.33 mm), 160/60 R14(1720.34 mm), 245/40 R17(1972.29 mm), 165/65 R14(1791.02 mm), 245/45 R20(2288.65 mm), 175/60 R14(1776.88 mm).