Car Tire Guide: How To Read Your Tires
Your car tires play a critical role in your safety while driving, so it is important that you understand as much as possible about the tires fitted in your car. This can also help improve your tire’s lifecycle, the car’s handling, and fuel efficiency over time.
Reading A Tire’s Sidewall
There is some information etched into the side of any car tire through which you can get some information about it. By learning how to read it, you will know the size of the tire, the model, the speed rating, and the load index.
The numbers on the tire’s sidewall are broken up as follows:
Example number – P225/50R17 98H
- Tire Type – The first letter on the set of numbers represents which type of vehicle this tire has been made for.
Tire Width – The next three numbers represent the width in millimeters. In the above example, the width is 225 millimeters.
Aspect Ratio – This is the ratio of the tire’s cross-section to the width. The first two numbers after the slash (/) is the aspect ratio. In the above example, the AR is 50, which means the tire’s height is 50% of the tire’s width.
Construction – This indicates the layers run radially across the whole tire. The most commonly found today is “R” which represents radial construction. Prior to new tires, old cars had a “B” which stood for bias-ply tires. These had poor handling and so were replaced.
Rim Diameter – This indicates the diameter of the rim of the wheel and is an important number for when you want to replace or upgrade the tire. In the above example, this number is 17.
Load Index – This number represents the total amount of load the tire can fully support when it is inflated. To know the proper load capacity, you will have to check a Load-Carrying Capacity Per Tire chart. In this case, it is 95 = 1521 pounds or 690 KG per tire.
Speed Rating – The final letter on the set represents the maximum speed capability of the tire. You can find the top speed using a Tire Speed Rating chart. H, in this case, means you can travel at 130 miles of 210 km per hour. More tire manufacturers recommend that you don’t exceed the speed limit mentioned on the tire as it can lead to failure.
The DOT symbol – If the tire has the word “DOT” etched into the sidewall, then it means that it is compliant with the Federal Motor Vehicle Safety standards set.
The TIN – The Tire Identification Number is the set of 12 letters and numbers that follow the DOT. These characters can be used to identify the location of the factory it was manufactured in, as well as the week and year it was manufactured. Example – “MA L9 ABCD 0315”.
- P – Passenger
- LT – Light Truck
- If there is no letter – Then it is a Euro metric tire
Make sure you only use the tire that is recommended for your car as specified in the vehicle manual. This way you won’t have any problems with control, handling, and functionality while driving.