225/40 R16 doesn't belong to the most popular dimensions for summer tyres - there are 1 tyre models available, which can be compared to
155/60 R15,
170/60 R17,
160/60 R14. Let's break down the sizing - 40 is height of the tyre, which is calculated as 40% of the tyre width (225mm), which means the sidewall height has 90 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 1842.23 mm, which is very similar to 165/70 R14
(1842.86 mm), 205/50 R15
(1840.97 mm), 195/40 R17
(1846.63 mm), 185/55 R15
(1836.26 mm), 195/60 R14
(1852.28 mm), 175/65 R14
(1831.86 mm), 205/45 R16
(1856.37 mm). There are multiple speed indexes available for summer tyres in 225/40 R16: W
(270km/h). The same goes for weight indexes: 85.
