255/65 R16 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 - 65 is height of the tyre, which is calculated as 65% of the tyre width (255mm), which means the sidewall height has 165.75 mm. The wheel diameter is R16, which means it fits to a 16 inch/406.4mm diameter wheel. The total circumference of the tyre is mm, which is very similar to 195/60 R15(1932.08 mm), 265/40 R18(2102.35 mm), 195/75 R16(2195.66 mm), 265/50 R20(2428.45 mm), 205/50 R15(1840.97 mm), 265/75 R16(2525.53 mm), 205/60 R16(2049.58 mm).