Compare255/45 R19 vs 245/50 R18. Tire Size and Comparison Calculator calculate tire diameter from code and compare speedometer differences for tire sizes. The first number 255 is the tire width in millimeters. The 2nd number 45 is used to calculate the MostPopular 275/35-R18 Comparisons. 245/45-R18 tires are 1.1 inches (28 mm) larger in diameter than 275/35-R18 tires and the speedometer difference is 4.1%. The245/40R18 Run Flat tire has the following features: the first three digits 245 refer to the width of the tire in millimetres. The second two-digit number 40 refers to the ratio between the height of the sidewall and the width of the tire. R stands for “Radial” and the last two figures 18 indicate the wheel diameter in inches. BetterFuel Economy Factory Ratios Increased Power. vs 275/35-19 vs 255/40-19 vs 255/35-19. 245/45-R18 tires are 0.04 inches (0.9 mm) smaller in diameter than 245/40-R19 tires and the speedometer difference is 0.2%. hje0Xn.

245 45 r18 vs 245 40 r18