A key safety aspect of any vehicle is the tyres. When properly maintained, your tyres play a large part in keeping you safe on the road, so here are a few things you should check:
- Tread Wear
- Temperature Resistance
- Their Maximum Load Capacity
- The Speed Symbol
- The Date of Manufacture
Different vehicles require different sized tyres. You can see the size of your tyres by checking the sequence of numbers and letters written on the sidewall of each tyre. For example:
185/55 R15 81H
185 indicates the Width – thus, the tyre width is 185 millimetres (the width is always measured in millimetres).
55 indicates the Profile / Aspect Ratio – thus, the profile is 55% of 185 millimetres. The depth of the sidewall of the tyre is the profile. The percentage of the tyre width (55%) is taken by measuring from the outer edge of the wheel to the outer edge of the tyre. In this instance, the measurement would be 55% of 185 which is equivalent to 102 millimetres (to the nearest millimetre).
R15 indicates the Rim Diameter – thus, the wheel rim diameter is 15 inches (the rim diameter is always measured in inches).
81 indicates the Load Index and H indicates the Speed Symbol – The Load Index is a number corresponding with the maximum load capacity of the tyre. The Speed Symbol is a category denoting the maximum speed at which the tyre can carry the load indicated by its load index. In our example, 81 means a maximum load of 462 kg per tyre and H means a maximum speed of 210 km/h. More information on the tyre load Index and speed symbol.
To test the tread depth of your tyres, place a matchstick between the tyre grooves. The tread should be more than 5mm deep, which is roughly equivalent to the head of a matchstick.
Run Flat Tyres
Some European and other cars have tyres designed to be able to be driven flat for a short distance. You can check if your vehicle has Run Flat Tyres fitted by checking for the letters ‘RFT’ inscribed on the sidewall of your tyres. If so, you can operate your vehicle after losing tyre pressure. Depending on the brand of tyre, you should drive no faster than 80 km/h for a maximum distance of 80 kilometres. Run Flat Tyres may only be fitted to vehicles capable of handling these tyres. Usually, this requires a vehicle with a Tyre Pressure Monitoring System (TPMS) operating.
A tyre’s resistance to heat is measured with ‘A’, ‘B’, and ‘C’ grades.
- A – Hot Area
- B – Normal Weather Area
- C – Cold Area
Each tyre is rated for its treadwear longevity. Some tyres will wear faster than others. The higher the number the longer it will take for the tread to wear down.
For example, a 400 grade tyre is likely to last twice as long as a 200 grade tyre.
Your ability to stop effectively in wet weather is reliant on the traction of your tyres. Traction ratings indicate which tyres will stop in a shorter distance on wet roads. So a higher letter will indicate tyres which are more effective at stopping in a shorter distance on wet roads.
Traction is graded from highest to lowest as ‘AA’, ‘A’, ‘B’ and ‘C’.
Rubber used to make tyres can break down, crack, harden, and even burst after a certain period of time. Therefore, the date of manufacture of your tyres, not the fitting date, is important. As a matter of safety, most vehicle tyres are given four years from date of manufacture to reach their expiry date. Please check the expiry date of your tyres carefully.
You will find four numbers stamped on your tyres, such as 1415. The first two numbers (14) refer to the WEEK of the year of manufacture. The second two numbers (15) refer to the YEAR of manufacture.
Therefore, 1415 means the 14th week of 2015.
To remain safe on the road, do NOT use expired tyres. They may harden and crack and – in the event of hot weather – possibly even burst.