Frequently Asked Questions
This is the tire size information. 225 refers to the tread width which is 225 millimeters. 50 stands for the aspect ratio, i.e., 50% of the tread width is the sidewall height. “R” indicates the radial type of construction and 18 represents the diameter of the wheel in inches for which this tire fits.
This is a high profile tire size with a section width of 225mm, a sidewall height of 50% of the section width, in this case, 225/2 = 112mm), a radial design, and a rim diameter intended for 18-inch wheels. Visit our online fitment guide today to find the perfect set of tires for your vehicle.
Even though the tread widths are the same and only the dimensions of the profile indicator are different, 50 and 40, a 225/50R18 tire cannot be directly substituted for a 225/40R18. The differences in the aspect ratios, 50% for 225/50R18 and 40% for 225/40R18, indicate a taller sidewall. This increased difference would change speedometer readings, clearances, and even the tire’s handling characteristics.
The majority of 225/50R18 tires have a recommended air pressure range of between 30–35 PSI when measured cold. However, the right pressure will depend on your vehicle's make and model so always check the owner's handbook before putting air in.
Most manufacturers recommend rotating every 5,000–8,000 miles to ensure that all four tires wear out evenly and to achieve the longest possible life for the tread. However, your rotation pattern could vary based on your alignment, driving behaviors, and even car type. You can check your vehicle’s owner’s manual to figure out the rotation schedule that suits you best.
