Probably the most fundamental area of your car that you need to be constantly aware of as a driver is the condition and suitability of the tyres that are fitted to your vehicle. As tyres wear, their ability to perform in certain road conditions deteriorates and, as a rule, you should be checking the condition of your tyres every time you prepare for a journey. Not only this, but when it comes time to replace your vehicle’s tyres, you need to be aware of the sizing and rating systems that tyre manufacturers use so that you can be sure that the tyres you wish to fit are suitable for your specific vehicle.
Printed on the sidewall of every tyre should be an alphanumeric code that describes not only the dimensions of the tyre, but also its ability in terms of maximum load bearing, maximum speed and in some cases the particular road conditions in which that tyre was designed for. Although the code may seem confusing at first, it is actually relatively simple to understand.
The first letter or letters in the code is called the vehicle rating and describes the type of vehicle that the tyre should be fitted to; ‘P’ for passenger vehicles, ‘LT’ for light trucks and ‘T’ meaning temporary (describing limited use, spare tyres). Immediately after the vehicle rating will be the aspect ratio of the tyre that describes the width of the tyre in millimeters, and then the depth of the sidewall as a percentage of the width.
The next subsequent code from the aspect ratio is the tyre construction method. Most passenger car tyres will have the code ‘R’ meaning Radial, though some tyres carry the codes ‘B’, ‘P’ or ‘D’; ‘B’ meaning belt bias, ‘P’ meaning cross-ply and ‘D’ meaning diagonal. After that code is the size in inches of the wheel that the tyre must be fitted to.
The last two codes relate to the speed rating of the tyre and the load index. The load index will be a two or three digit number that defines the maximum total weight the tyre has been designed to withstand. If you are unsure of what rated tyres you should fit, you can find out by researching the driver’s manual or by contacting your manufacturer. The speed rating will be a single letter or the letter A and a number that tells you the highest speed that that particular tyre has been designed to be run at. If you fit tyres to a car that is able to exceed that speed, you could be invalidating your insurance, aside from the legalities of traveling at that speed.
Read On : Tyres Online