What Do the Model Specifications of Tires Represent?
2 Answers
The parameters displayed on the tire model represent the tire's width, aspect ratio, type, and applicable size. Most tire model markings appear as: 215/70R15. The meanings of these numbers are as follows: 215 indicates the tire section width in millimeters (mm), generally ranging between 145—285mm with intervals of 10mm; 70 is the aspect ratio, representing the ratio of the tire sidewall height to the tire section width, where 70 stands for 70%. Typically, tire aspect ratios range from 30% to 80%. Under normal circumstances, ordinary sedans should not use tires with an aspect ratio >75%, while luxury cars and high-performance sports cars are recommended to use tires with an aspect ratio <60%; R is the abbreviation for Radial, indicating that the tire has a radial structure, and 15 is the rim diameter in inches. If a tire is marked as 6.00—12, it indicates that it is not a radial tire but a bias-ply tire. Such tires are rarely seen on passenger cars today due to their poor safety, load capacity, and high-speed stability, and are only used in some low-end off-road vehicles and heavy-duty trucks. Tire Types: PC—Passenger Car Tire; LT—Light Truck Tire; TB—Truck and Bus Tire; AG—Agricultural Vehicle Tire; OTR—Off-The-Road Tire; ID—Industrial Vehicle Tire; AC—Aircraft Tire; MC—Motorcycle Tire.
Tire codes like 205/55 R16 always felt like little puzzles to me. The 205 stands for width in millimeters, 55 is the aspect ratio (height as percentage of width), R means radial construction, and 16 is the rim diameter in inches. Last time I changed tires, I didn't pay attention and bought slightly oversized ones - ended up with terrible road noise and skyrocketing fuel consumption. Had to switch back to OEM specs immediately for comfort. Width affects grip and cornering stability, while a 55 aspect ratio offers balanced performance - higher ratios cushion better but respond slower, lower ones give precise steering but a harsher ride. I always check tread wear and pressure during maintenance. Using correct specifications saves fuel and extends tire life - never skimp on this. Always check your door sticker or manual before buying new tires.
