The tyres on your car do not last forever; they can become damaged or the thread can be worn down to a dangerous level. This is when you need to buy new tyres. You can choose to buy online, or head to a nearby dealership.
You may want to choose a specific type of tyre, such as the Michelin pilot sport 4, if you have a high end sports vehicle. Whatever type of tyre you are thinking of buying, you need to know which size of tyre is right for your vehicle.
Where to find the size of tyre that you need
You probably do not know what size of tyre you need to buy, so you should take a look at the sidewall of one of the current tyres. There will be a number there which indicates the right tyre size to use. The number is usually small, so you may need to look closely to find it.
What does the number mean?
The size that you will find on the tyres of your car is made up of several different letters and numbers which represent different things.
- The first three numbers represent the width of the tyre from the inner sidewall to the outer sidewall. The width is measured in millimetres. It’s important to use industry standard rims as they affect the total width of the tyre.
- The next set of numbers is the aspect ratio. This is the ratio of the width of the tyre with the height of the cross section. High performing tyres have an aspect ratio of below 60.
- The letter which normally comes next in the sequence is the type of construction of the tyre, for instance radial.
- The following couple of numbers represent the rim diameter. The diameter is the distance from bead to bead on the rim and it’s measured in inches. Most tyres have a rim size of between 12 and 28 inches, with the average rim diameter being 15-17 inches.
- The next numbers in the sequence tell you the load index of the tyre. This is the maximum load capacity possible if tyres are inflated as they should be.
- Next in the sequence, you will see a letter. This is the speed rating of the tyre which indicates the maximum speed at which the tyre is safe to be used on a car. For instance, a speed rating of V indicates that the tyre will perform safely up to a maximum speed of 1
All of the figures are important as they make the overall tyre size. It’s important that you stick to this same size when you buy new tyres for your car. If you have difficulty finding the size on the sidewall of the current tyres, you should also be able to find the details in the owner’s manual for the vehicle.