Meaning of Numbers & Letters Inscripted on Car Tyres

Photo collage between a car tyre and different words inscribed on the tyre.
Photo collage between a car tyre and different words inscribed on the tyre.
Motors Auto

Every car tyre bought from an authorised manufacturer bearers specific numbers with distinct meanings that all motorists need to understand before making purchases

Other than the size, each number and letter indicate the amount of load a tyre and support and even the maximum speed a car can move without losing its stability. 

For instance, a car's tyre can have the following numbers and letters: 197/57R/17/93H. However, the numbers and letters differ, but the format is similar.

197

 

A car tyre with different letters and numbers inscribed on top
A car tyre with different letters and numbers inscribed on top.
Stuff.nz

The three digits indicate the width of the tyre in millimetres. It represents the size of a car's tyre.

57

The next two digits following the first slash represent the aspect ratio. This is the height of the tyre as a percentage of the width.

R

After the numbers that indicate the aspect ratio, there is a letter. In most cars, R comes after the numbers. R stands for Radial.

Radial means that the steel belt's inner construction is angled at 90 degrees to the direction of travel, resulting in extra strength.

Most mechanics base on radial to replace tyres.

17

The two digits after radial indicate the diameter of the wheel.

Matatu drop-off stage at GPO along Kenyatta Avenue in Nairobi.
A photo of a matatu drop-off stage at GPO along Kenyatta Avenue in Nairobi taken on May 23, 2022.
Kenyans.co.ke

For instance, 17 indicates it can fit in a 17-inch wheel rim.

93

93 represents the load index which represents the maximum load the tyre can carry when correctly inflated.

Each double digit is essential as they represent different weights in kilogrammes.

According to experts and car enthusiasts, overloading is dangerous and can affect the car's handling and stability.

Carrying weight above what is indicated on the tyre also leads to increased fuel consumption.

H

The final letter represents the speed rating of the tyre. This is the maximum speed that the tyre can cope with under its maximum load. 

Each letter represents a corresponding speed.

Exceeding the speed indicated on the tyre may lead to accidents and busts.

Other writings on a tyre include the manufacturer, manufacturing date, temperature and certification issued by the Kenya Bureau of Standards.

A tyre with different numbers and letters with their meanings
A tyre with different numbers and letters with their meanings.
Indian Auto
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