What unit is used for tires?
3 Answers
Automobile tires are measured in millimeters, indicating the section width and aspect ratio percentage. Below are the functions of car tires and precautions for their use: Functions of car tires: Support the entire weight of the vehicle, bear the load of the car, and transmit forces and moments in other directions; prevent automotive components from suffering severe vibrations and early damage, adapt to the high-speed performance of the vehicle and reduce driving noise, ensuring driving safety, handling stability, comfort, and energy-saving economy. Precautions for using car tires: Owners should promptly remove foreign objects from the tires to prevent stubborn stones from getting stuck in the tread. When the tire wears to a certain extent, these objects can puncture the tire body, leading to air leakage or even a blowout. Rotate the tire positions every 10,000 kilometers to evenly distribute tire fatigue and prevent uneven wear, thereby extending tire life.
I remember being a bit confused when I first changed tires and saw those numbers on the sidewall. The tire width is indicated in millimeters, for example, 225 means the tread is 225mm wide. The aspect ratio percentage is quite interesting - my previous car had 55, meaning the sidewall height is 55% of the width. The wheel size is actually marked in inches, with 17 or 18 being most common. The tire technician said I should also pay attention to the speed rating letter and load index number - since I do a lot of highway driving, I chose H-rated tires. All these units combined determine the correct tire model. Even a slight difference in size can affect handling and fuel consumption, so it's best to note down the original factory specifications before buying new tires.
I often ponder about car parts, and the tire size markings are indeed unique. The width is directly labeled in millimeters, the aspect ratio is written as a percentage after a slash, and the rim diameter is in inches, combined like 225/55 R17. Last time when I accompanied a friend to change rims, I learned that choosing tires isn't just about the appearance; the load index number and speed rating letter are equally crucial, otherwise the car might feel unstable at high speeds. Different units represent different performances; off-road tires might emphasize tread depth in millimeters, while snow tires might prioritize low-temperature parameters.
