What does the car tire size 225/50r18 mean?
2 Answers
The car tire size 225/50r18 means the tire has a cross-sectional width of 225mm, an aspect ratio of 50%, 'R' stands for radial tire, and a diameter of 18 inches. Below is an introduction to the tire specification location and how to read it. Tire specification location: The original tire size of a car can be found in the owner's manual, on the border of the left front door, on the storage compartment door, or on the fuel filler cap. You can also find the tire specification information on the sidewall of the existing tire. How to read tire specifications: For example, if the tire specification is 195/65R1591V, '195' indicates the tire width is 195mm; '65' indicates the ratio of the tire's section height to width is 65%, which is the aspect ratio; 'R' stands for RADIAL, meaning it is a radial tire; '15' indicates the rim diameter is 15 inches; '91' indicates the load index; and 'V' represents the tire's speed rating.
When I first started learning to drive, I was completely baffled by the numbers like 225/50R18 on tires. Later, a friend explained that it's like the tire's ID card. The 225 stands for a width of 225 millimeters, slightly wider than a fist, affecting grip and fuel consumption; 50 is the aspect ratio, meaning the tire's height is only 50% of its width, approximately 112 millimeters, indicating the height-to-width ratio—lower height means more precise handling but a bumpier ride; R denotes radial construction, which most modern tires use for durability; and 18 refers to the rim diameter of 18 inches, which must match the vehicle's design. You can't randomly change tire sizes—I once tried a slight difference of a few millimeters and felt unstable braking, especially in rain or snow, which was dangerous. I recommend beginners check their vehicle's manual first to confirm the original tire size—safety comes first.
