How to read a tire?

Published on : 05 November 20194 min reading time

Tires allow your vehicle to be comfortable on the road. But to choose the right tire for your car, you must know how to read it. All the information on this one has a meaning. This information is crucial to optimize your car. On a tire, you can find many elements such as size, load index, speed index, height, date of manufacture, model, dimensions, etc. It is also possible to define whether they are summer or winter tires.

Dimensions and load index

We will take as an example 195/65R15 91V.

195: the section or width of the tyre which is expressed in millimetres

65: the ratio between the height of the tire and the section which is expressed as a percentage. It therefore informs about the height of the sidewall or the thickness of the tire

A: The radial structure of the tire. We also have D, for diagonal

15: the inner diameter or rim diameter in inches

91: the load index

V: the speed index

When using a tire comparator, it is important to know the specificities of the tires you are looking for. Indeed, buying tires without knowing exactly what to consider is not always easy. That’s why we need to be well informed first.

Otherwise, index 91 means that the tyre can support a maximum load of 615 kg. When you want to change it, you can increase it by a higher load index, but it is not advisable to choose a lower index. This means, among other things, that a 92-index tire can support a load of 630 kg, and obviously, it can therefore support a 91-index equivalent to 615 kg of load. You can compare tire prices online to find the right ones for your vehicle.

The speed indexes

The speed index is indicated by a letter. It allows you to know the maximum speed that can be reached with the tire. It is forbidden to go down a speed index, but you must go up one or more. Even if you do not drive at the maximum speed supported by the tire, a lower speed index is not tolerated. Except for the mounting of a winter tire where one or two clues can be reduced compared to the original summer mounting. Otherwise, we may have to pay fines for safety reasons. These speed ratings range from A to Y. A being the lowest index and Y the highest, except for H which is between U and V. Each index has its equivalent in km/h, for example H equals 210 km/h, V equals 240 km/h, and Y equals 300 km/h. Also, with a tire price comparison, you can find the best tires at the best prices.

DOT, brand and model

It is easy to notice the models and tire marks on the sidewall. Then, thanks to a code called DOT (Department of Transportation), we can know where and when the tire was built. For example, DOT 4B9Z 747R 2609 means:

– 4B: Code of the factory where the tire was manufactured

– 9Z: Manufacturer’s dimension code

– 747R: Manufacturer’s specific code

– 2609: Date of manufacture of the tyre

The last 4 digits of the code indicate the year and week of manufacture. For example, 2609 means that it was manufactured during the 26th week of 2009. It is advisable to replace a tire with a DOT greater than 10 years old, even if its tread is quite thick. Otherwise, it is easy to differentiate a winter tire from a summer tire thanks to their patterns and the M + S (mud and snow) code for snow tires. And a summer tire has no default markings.

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