How to Read Tire Size? Can I Upsize?

Taking the common 225/45 R18 95W as an example, each segment corresponds to a specific parameter meaning:

225: Tread width, measured in millimeters.

A larger value means a wider contact area between the tire and the road, enhancing grip but also increasing fuel consumption accordingly.

45: Aspect ratio, which refers to the percentage of the tire sidewall height relative to the tire width.

A smaller value indicates a thinner sidewall, providing more road feedback but less vibration damping comfort.

R18: R stands for radial tire

(the current mainstream structure for passenger vehicles), and 18 indicates compatibility with a 18-inch diameter wheel hub. The wheel hub size must perfectly match the tire for installation.

Load Index 95: Corresponds to a maximum safe load of approximately 690 kg per single tire, with a total load capacity of 2,760 kg for four tires. The load must not fall below the manufacturer's specified standard.

W: Speed rating

indicating that the maximum safe speed for this tire is 270 km/h. Common speed ratings for daily passenger vehicles include V (corresponding to 240 km/h) and H (corresponding to 210 km/h).

Impact of Increasing/Expanding Width:

-The speedometer reading is inaccurate (actual speed is higher than indicated)

- May scrape the wheel arch or damage the inner lining when turning to the limit

- Increased fuel consumption and odometer deviation

- Some vehicle models may trigger ESP/ABS alerts

- Upgrades must be performed within the manufacturer's approved limits