Thiswill consist of four digits – the first two refer to the week your tyre was manufactured and the last two refers to the year. For example, if the marking on your tyre reads 3820, this means the tyre was made in the 38th week of the year during 2020. Manufacturer. OE Markings. Audi. Tire1 / R 225 45 R 18 Tire 2 / R 225 40 R 18 Inch Mill KPH MPH Odometer Reading If you replace 320/60/18 with 235/60/18 for Odometer reading 1000 the actual distance traveled 22550-R18 tires are 0.39 inches (10 mm) larger in diameter than 215/50-R18 tires and the speedometer difference is 1.5%. Forthe record, the difference in circum. between the 215/40 and 225/45 is 3.77 inches, not 2 1/2 inches; there is only 0.99" difference between OEM and 225/40. Yes, you're correct. But I was referring to the circ. diff between 225/40 and 225/45. The numbers are actually 78.81 for 225/40 and 81.59 for 225/45. I was rounding down to an even number. Inthe tire comparison table above, you can see a detailed calculation of the size difference between 225/40 R18 and 205/55 R16 tire. The calculation results are presented in the form of visual infographics, on which tire with size 225/40 R18 is on top, and tire with size 205/55 R16 below. Both in the table and in the graph, the tires are Compare225/50 R18 vs 215/60 R17. Tire Size and Comparison Calculator calculate tire diameter from code and compare speedometer differences for tire sizes. The first number 225 is the tire width in millimeters. The 2nd number 50 is used to calculate the sidewall height or "aspect ratio", by percentage. So, the sidewall height of a 225/50 R 18 Thedifference in sizes and parameters between the 235/45 R18 tire and 245/45 R18 tire. Detailed calculations and graphics. Calculate the difference in inches. 225/50 R18: 225/45 R18: 215/60 R16: 245/40 R18: 225/55 R17: 225/50 R17: Sizes often compared to the 245/45 R18 tire: 245/40 R18: 225/45 R18: 5th 2023 AutoBild UHP Summer Tyre Test (225/45 R18) 13th: 2023 Summer Tyre Market Overview (225/45 R18) 2022 Tyre Tests; 7th: 2022 Summer Tyre Market Overview (215/55 R17) 8th: 2022 Auto Bild Summer Tyre Test (215/55 R17) 2021 Tyre Tests; 4th: 2021 EVO Summer Tyre Test (225/40 R18) 5th: 2021 Motor Summer Tyre 24540-R18 tires are 0.1 inches (2.5 mm) larger in diameter than 215/45-R18 tires and the speedometer difference is 0.4%. Inthe tire comparison table above, you can see a detailed calculation of the size difference between 225/60 R18 and 225/50 R18 tire. The calculation results are presented in the form of visual infographics, on which tire with size 225/60 R18 is on top, and tire with size 225/50 R18 below. Both in the table and in the graph, the tires are dFqD.