The first number 225 is the tire width in millimeters. The 2nd number 55 is used to calculate the sidewall height or "aspect ratio", by percentage. So, the sidewall height of a 225/55 R 18 tire is 60% of 225 = 192. The 3rd number 18 (generally preceded by an "R") is Rim Diameter in inches. In the tire comparison table above, you can see a detailed calculation of the size difference between 225/45 R18 and 245/45 R18 tire. The calculation results are presented in the form of visual infographics, on which tire with size 225/45 R18 is on top, and tire with size 245/45 R18 below. Both in the table and in the graph, the tires are In the tire comparison table above, you can see a detailed calculation of the size difference between 275/40 R18 and 245/45 R18 tire. The calculation results are presented in the form of visual infographics, on which tire with size 275/40 R18 is on top, and tire with size 245/45 R18 below. Both in the table and in the graph, the tires are 215/50-R17 tires are 0.38 inches (9.6 mm) larger in diameter than 225/40-R18 tires and the speedometer difference is 1.5% 225 vs 235 tires: So when someone mentioned their tire size is 225/45 R17, what does this actually mean? 225 actually denotes the width of the tires in mm. For example a 225/45R17 tire size, it means that the width of the tire is 225mm (~ 8.9 inch) wide. The picture below shows an illustration of the 225mm length tire width. 225/40 R18: £102.69 - £108.70 (2 Prices) Compare Prices >> 225/45 R17: £95.88 - £111.64 (10 Prices) Compare Prices >> 225/55 R17: £138.63 - £161.53 (8 Prices) Compare Prices >> 235/45 R17: £117.05 - £127.96 (5 Prices) Compare Prices >> Available in 47 tyre sizes - View all. mHHV.

225 45 r17 vs 225 40 r18