A tyre must be replaced
Never choose a smaller tyre than the size that came with the car. Smaller Tyres may not be able to support the loaded weight of the vehicle. Tyres should always be replaced with the same size designation or the approved sizes recommended by the auto/tyre manufacturer or a tyre professional.
Tyres with different size designation, constructions, and amounts of wear may affect vehicle handling and stability. For best all round performance, the same type of tyre should be used in all four wheel positions. Special purpose Tyres can be used to improve performance in some applications. Some Tyres, such as speed rated constructions may also have special matching requirements. Get specific information from a tyre professional. It is possible to mix your present Tyres with other size designations or constructions. However, Tyres of similar size and similar construction must be used in pairs on the same axle. When radial Tyres are used with bias or belted Tyres on the same car, the radials must always be placed on the rear axle.
Tyre mounting is a job for people who have the proper equipment and experience. Most tyre retailers offer free mounting service on purchase of new tyres. If you try to do the mounting on yourself, the risk of a serious injury or possible damage to the tyre beads and rim is unavoidable.
The new tyres on the car may feel different from the Tyres that were replaced. Drive carefully until familiar with their performance and handling. Take special care when braking, accelerating, cornering or driving in the rain. These are the times when any differences will be most noticeable.
The valve is a very important element, contributing to the air tightness of the tyres / wheel assembly. Under the centrifugal force, when the car is traveling at 80kmph, the force acting on the valve makes it equivalent to a mass of 1.7 kg, nearly 2 bags of sugar. So during use, it deteriorates with age.
It is therefore essential to have the valves replaced every time the tyres are changed. It could be a false economy to compromise the life of the tyres, or even your personal safety, for the sake of a new valve. There are different sizes (TR-413, TR-414, TR-418) and finishes (Metal, Rubber, Chrome) of valves available in the market check with a tyre professional for the correct size of the valve which would suit the tyre in your car.