What is on the sidewall of a tire?
The numbers and letters on a tire’s sidewall provide essential information about the tire’s size, construction, load capacity, and speed rating. Knowing how to read these markings helps you choose the right tire for your vehicle and ensures safe and proper performance.
We help break down what each number and letter means so you can shop with confidence.
Tire Type
If the tire number starts with a P this indicated the tire is made to fit US standards, meaning it is a P-metric tire for use in passenger vehicles. With no letter in front of the numbers it is a Euro metric tire. If there are the letters LT this means they were made for light trucks.
Tire Width
The tire width is measured in millimeters starting from one sidewall to the other. For example, a tire sold on OTRUSA.COM has 315/80R22.5 on its sidewall then the width is 315 millimeters.
Aspect Ratio
The next indicator is the aspect ratio, this is the tire height measured from the cross section to the width. In this case the number is 80 meaning that the height equals to 80% of the width of this tire.
Construction Type (Radial vs Bias)
Next, you will see a letter; this indicates what type of tire it is. For example, This tire has an R letter meaning it is a Radial tire. In a radial tire the tread and the sidewall function independently, more power is transferred onto the road. A bias tire on the other hand is made from multiple layers of rubber overlapping making the sidewall and the crown work as one. There are both types of tires available at OTRUSA.COM
Wheel Diameter
The last number tells us what the wheel diameter is. The diameter is measured from one end to the other. This is the size of the wheel needed to use with the tire. The tire with the numbers above is made to be used with a 22.5 diameter wheel.
Load Index and Speed Symbol
You will also see a number such as 156/150L. This is the load index and speed symbol. The load index tells you the maximum load the tire can support. The speed rating tells you the highest speed the tire can handle.
DOT Symbol and Safety
There may be a DOT symbol on the tire telling you the tire complies with the vehicle safety standards in the US. Right next to the DOT are 12 numbers and letters called tire identification number. This is like a serial number and helps indicate the company who produced the tire, when the tire was made, and where the factory is located.
Not sure which tire you need?
Contact us today, and we’ll find the perfect match for your machine.
About OTRUSA.COM
OTRUSA.COM is a tire wholesaler with over 20 years of experience. We specialize in industrial tires, including agricultural tires, truck tires, tire wheels, protective chains, and tire pressure monitoring systems.