Understanding what your tyres are trying to tell you.

To understand the narrative of your tyre is important for you and for me.

In an very small sampling I discovered that most people have no idea what the information outlined on the sidewall of their tyres is trying to tell them, and even more alarming, not one of those to whom I spoke had even looked at their tyres in any meaningful way. To be honest and open I was one of those people, so I thought I had better develop my own information about something so critical and share the knowledge gained.

I have tyres that display the following markings as to size. 225/60 R 16 98V M+S. This number is inscribed on my ITV (MOT) document, which means that I must drive with this size tyre, or an acceptable form of same.

225 is the width of the tyre tread in mm. A wider or, I suppose a more narrow tread may be acceptable, but this is the factory fitted size.
60 is called the aspect to ratio, meaning the size of the tyre wall is, in this case 60% of the width.

R indicates that this is a Radial type, which means having the core fabric layers arranged radially at right angles to the circumference and the tread strengthened.

16 is the diameter of the wheel size the tyre is to fit, and is expressed in inches.
98: This is the maximum weight capacity of the tyre according to the official index table. In the table this translates to 750 Kgs.
V: This indicates the maximum speed at which the vehicle can be driven that the tyre can support. The index table rates this as 240 km/h or 149 mph. Presumably this will never be tested on a family car.

I have no idea what the M+S means.

There is a four number stamp that is important because the numbers indicate the manufacture date. The first two numbers reflect the week during the 52 weeks of the year that they were pressed, and the other two numbers are the year of manufacture.

There are other stamps that are of a technical nature that reflect such data as noise rating and approval stamps of various authorities. There is also a warning as to under and overinflation, but the one thing that is often missing is the normal pressure rating.

These are factors to keep in mind should you wish to replace the factory tyres with others. Having oversized tyres may seem cool, but they are not likely to pass muster at ITV and they may not be safe.

Copyright (c) 2013    Eugene Carmichael