Knowing your tyres...

Did you know that the pattern on your car’s tyre treads are different, depending on what type of vehicle you have and what your vehicle’s purpose is? For example, a rib shape is generally used for paved road surfaces. Whereas an asymmetric pattern, which differs from side to side, reduces the tread wear on the outside of the tyre due to its greater contact area, meaning it is ideal for high performance and motorsport tyres.

The primary function of the tyre tread is to ensure a strong grip on the road remains consistent, as well as to prevent the car from aquaplaning in wet weather. The legal limit for tread depth is 1.6mm, any less than that and you are at risk of three points on your licence, as well as a hefty £2,500 fine. Although by law the limit is 1.6mm, many manufacturers recommend that you should have them changed when the depth reaches 3mm as ‘at 1.6mm in wet weather, it would take an extra two car lengths (8 meters) to stop at 50mph.

A sure way to measure this is to buy a tread depth indicator gauge, however, another way is to simply use the 20p test. All you need to do to carry out this test is to place a 20p coin into the groove of the tread and if the outer band on the coin is covered then you should be safe. You should carry out this test on the whole circumference of the tyre to check for any irregular wear as this may indicate wheel misalignment.

As well as tyre tread, you should also check for any abnormal bulges on the sidewall of your tyre. A bulge may suggest that the metal frame within the tyre is been damaged which could be caused by a number of things, including driving through a pothole or over a curb, or even driving with low pressure. It is important to have these checked immediately as it reduces the structural integrity of the wheel, which increases the risks of failure or even a blow out.

NB: According to the NHTSA (National Highway Safety Administration) you must get your tyres replaced every six years.

As well as the above, it is important to check your tyres for any cracks in the outer rubber as this could indicate dry rot, which may occur in cars with infrequent or lack of use.