Truck tire markings contain crucial information about size, load capacity, speed rating, and other technical specifications. Understanding truck tire markings helps you choose the right tires, ensuring safety and optimal vehicle performance. This article provides a detailed guide on how to read and understand truck tire markings.
1. Manufacturer and Tire Type
Truck tire markings usually begin with the manufacturer’s name and logo, such as Continental, Goodyear, Kumho, Bridgestone, etc. The letter “C” on the tire indicates that it is designed for heavy-duty trucks and commercial freight transport.
Logo of a tire manufacturer on a truck tire sidewall.
2. Truck Tire Size
Truck tire markings express tire size through a series of numbers and letters. For example: 315/80R22.5
2.1 Tire Width
The first number in the truck tire marking (e.g., 315) represents the tire width in millimeters (mm), measured from sidewall to sidewall.
Diagram illustrating how to measure tire width from sidewall to sidewall.
2.2 Aspect Ratio
The next number (e.g., 80) is the aspect ratio, which is the percentage of the sidewall height to the tire width. A larger ratio means a thicker sidewall.
2.3 Rim Diameter
The number after the letter “R” (e.g., 22.5) indicates the rim diameter in inches. This is the size of the rim that the tire is designed to fit.
Image showing measurement of rim diameter in inches on a truck wheel.
3. Maximum Load Capacity
Truck tire markings include a load index (e.g., 152/148). This number indicates the maximum load a tire can carry when properly inflated. A higher index means a greater permissible load.
Table or chart showing load index values and corresponding maximum load capacity in kilograms.
4. Maximum Speed Rating
The letter after the load index (e.g., L) indicates the maximum speed the tire can withstand. Each letter corresponds to a specific speed rating. For example:
- L: 120 km/h
- M: 130 km/h
- N: 140 km/h
- P: 150 km/h
- Q: 160 km/h
- R: 170 km/h
- S: 180 km/h
- T: 190 km/h
- U: 200 km/h
- H: 210 km/h
- V: 240 km/h
- W: 270 km/h
- Y: 300 km/h
- Z: Over 240 km/h
Table listing speed symbols and their corresponding maximum speed ratings in km/h.
5. Other Markings
In addition to the main specifications, truck tire markings may also include:
- Heat Resistance Index: (A, B, C) indicates the tire’s heat resistance capability.
- M+S Symbol: Indicates that the tire is suitable for muddy or snowy road conditions.
- Tire Pressure Index: Shows the maximum permissible inflation pressure.
Examples of other tire markings like heat resistance index, M+S symbol, and tire pressure index on a tire sidewall.
6. Example of Reading Truck Tire Markings
Truck tire marking: 315/80R22.5 152/148L
- Width: 315 mm
- Aspect Ratio: 80%
- Rim Diameter: 22.5 inches
- Load Index: 152/148 (single/dual load)
- Speed Rating: 120 km/h (L)
Example of a truck tire marking 315/80R22.5 152/148L with explanations of each part.
7. Conclusion
Understanding truck tire markings is crucial for choosing the right tires, ensuring safety and performance for your vehicle. Always refer to the manufacturer’s guidelines and consult with experts to select the best tires for your truck.
