24545-R18 tires are 2.42 inches (61.5 mm) smaller in diameter than 235/60-R18 tires and the speedometer difference is 8.3% 24545-R18 tires are 1.28 inches (32.5 mm) larger in diameter than 235/40-R18 tires and the speedometer difference is 4.8%. Witha diameter of 25.72 inches, the 245/40R18 provides 0.31 inches (8mm) more ground clearance than the 235/40R18 at 25.4 inches. This extra clearance is useful for off-road driving over obstacles and rough terrain. However, the larger 245/40R18 diameter causes a slightly lower speedometer reading than the 235/40R18 one. Both235/x/18 sizes are appropriate for that car. I believe the 235/45/18 was the tire size used in all the later S60s with the 18" wheel option, but the 235/40/18 would fit just fine, too, albeit with a smaller overall diameter (by exactly an inch, if memory serves) compared with the 235/45/18 version or 235/40/19 tire. 23545-R18 tires are 0.61 inches (15.5 mm) larger in diameter than 245/40-R18 tires and the speedometer difference is 2.3%. The2nd number 50 is used to calculate the sidewall height or "aspect ratio", by percentage. So, the sidewall height of a 235/50 R 18 tire is 60% of 235 = 192. The 3rd number 18 (generally preceded by an "R") is Rim Diameter in inches. This is the diameter of the rims bead seat base, not the diameter of the outer rim edge. Compare215/55 R17 vs 235/45 R18. Tire Size and Comparison Calculator calculate tire diameter from code and compare speedometer differences for tire sizes. The first number 215 is the tire width in millimeters. The 2nd number 55 is used to calculate the sidewall height or "aspect ratio", by percentage. Also the online application calculates the difference in real speed and speedometer readings if the difference between tire 235/60 R18 and tire 235/70 R18 is significant. Calculate the difference in inches. If you want to compare other tire sizes, then select their sizes in the drop-down fields and click on the green button. .

235 45 r18 vs 235 40 r18