Keeping your tyres in excellent condition is vital to your driving safety. Properly inflated tyres give your car better stability, braking, handling, and it prevents tyre failure. It will also save you money as it extends their life expectancy. Driving on soft tyres is not only unsafe, but it will also consume more petrol as they add to rolling resistance, meaning your car has to work harder.
It’s normal for car tyres to wear over time, you’ll have to get them replaced at some point. Too little tread can cause the car to slip and slide, while tyres that are bloated or blistered are at risk of popping and potentially causing a risky situation or even a serious accident. Depending on how much driving you do, you should update your tyres at least once every 5 years, after that they start to lose the UV anti-aging protection and will become worn down.
But how do you spot if your car tyres are worn and need to be replaced? To help below is a summary of the types of tyre wear for you to look out for:
Types of tyre wear
Outside wear (underinflation) – When the outside of the tyre is wearing down faster than the rest of the tread, leaving bald stripes on the edges, this can be an indication of under inflation. In most cars, the vehicle manufacturer’s tyre pressure specifications are labelled along the door jam. The vehicle owner’s manual will also state tyre pressure recommendations and the tyres themselves will have the psi (Pounds per Square inch, a unit used to measure air pressure inside a chamber that contains gas) or bar (a unit of pressure equal to 100,000 pascals) imprinted in the rubber. Many drivers don’t realise their tyres have lost air because it travels slowly through the rubber and at interfaces with the wheel and valve. Temperature can also be behind a pressure drop as the pressure in cooler air is lower, causing the tyres to become softer.
Centre wear (over inflation) – When tyres are overinflated, the centre of the tyre wears down faster than the rest. If you’re not already doing so, start checking your tyre pressure at least once a month. A tyre pressure gauge the size of a pencil can be bought from auto parts centres, or used at a service station or tyre centre. Pressure increases as the tyres start to rotate and heat up, therefore a more accurate reading can be gained when the tyres are cold – e.g. in the early morning or when the car has been sitting idle for some time.
Feather wear – Feathering happens when on one side of the tyre the thread ribs have rounded edges, while the other side has sharper ones. Feathered tyres are often a sign of improper wheel alignment, which happens when your tyres are not all pointing in the same direction, causing them to lean too far outwards or inwards. This is why it is important to have your tyres aligned each time you have them changed or have it checked during every service.
Wear on one side – This type of irregular tread wear, also called camber wear, is caused by the tyre tilting to one side and putting too much pressure on its shoulder. As a result, the inside or outside shoulder rib of the tread gets more worn than the other ribs. Your car steering to the left or right when travelling can be an indication of this problem. It can be fixed by re-aligning the wheels, but in some cases, it could be due to sagging springs, worn ball joints, or worn control arm bushings, which may require replacing.
Cupping wear – Cups or scalloped dips on the edge of the tread caused by slight frequent bouncing. Generally, rhythmic vibrations or a shake can be felt while driving at speeds above walking pace, which is usually an indicator of worn or bent suspension parts. Best is to see a professional tyre centre or mechanic as soon as possible to have this problem fixed.
Second-rib wear – Second-rib wear appears on the ribs second from the inside or outside of the tyre, where the steel belts end in relation to the tread. Usually, it is found only on radial tyres and is regarded as normal but it can be a sign that your tyres are too wide for the wheels, especially if you have traditional tyres with diagonal nylon plies. Normally, it can be kept to a minimum by frequently rotating the tyres and paying careful attention to tyre pressure.
Other indicators of tyre wear
Besides the above types of tyre wear, there are other indicators you should check your car tyres for on a regular basis:
Tread too low – The tread of a tyre in Australia legally has to be more than 1.5 mm. But that’s the absolute bare minimum. If you regularly drive on wet and slippery surfaces, it would be wise to stick with twice that. The higher the tyre tread the more grip the car has and can navigate better on wet, muddy, gravel, or snowy surfaces. Today, car tyres have several tread wear bars located in the grooves. They’re invisible when the tyre is new but begin to appear gradually once the tyre gets worn. When the grooves lose most of their thread, these bars become visibly flushed with the adjacent ribs, which indicates it’s time to replace the tyre.
Side-wall damage on tyres – It’s not just the tread of the tyre that needs to be checked. You also need to look out for scratches, indents or weak spots that are visible on the side wall of the tyre. Depending on the size and severity of the damage it could indicate a leak or that the tyre could be about to pop, so it’s best to have the mark checked by a mechanic as soon as they appear.
Bulges and blisters on the tyre – These occur when the outer sides of the tyre become worn down and begin to weaken. A bulging or split tyre could cause a blowout at any time, so if you have one, the tyre needs to be replaced or taken to a mechanic or tyre centre immediately.
Too much vibration while driving – This could be an indication of a problem within the tyre or with the shock absorber. If you’ve been driving the car for a while you will already have an indication of how much vibration is normal, but if you sense too much it could also mean the tyres are misaligned or unbalanced.
Although car insurance does not cover for costs for the replacement of new tyres in case they are worn, it can cover you in case of emergency repairs and towing costs if you were involved in an accident. Having well-maintained tyres is just as important for your car as having comprehensive car insurance for safety and peace of mind.