Your tyres have a use-by date stamped on the sidewall, and most people never check it. Rubber hardens with age even when the tread looks fine. Knowing when to replace them is about more than passing a roadworthy.
Tyres are the only contact between your car and the road. Everything the car does, stopping, turning, holding a line in the wet, depends on four palm-sized patches of rubber. Worn or old tyres make every other system in the car work harder. Here is how to tell when a set is due.
In Australia, the legal minimum tread depth is 1.5 millimetres across the full width of the tread. That is a legal minimum, not a recommendation to run your tyres to it. A tyre at 1.5mm takes longer to stop in the wet than one at 3mm, and the difference gets worse as the tread gets shallower. The tread pattern exists to channel water away from the contact patch. When there is not enough depth left, the water has nowhere to go and the tyre rides on top of it. That is aquaplaning.
You can check tread depth with a gauge, or look for the tread wear indicators built into the grooves. They are small bars that sit across the groove. When the tread wears down to the same level as the bar, the tyre is at the limit. You can find more detail on the VicRoads website.
Tyres degrade with age whether they are driven on or not. The rubber compounds harden and lose grip, and the casing can develop cracks that you cannot see from the outside. A tyre that is ten years old with plenty of tread is still a tyre that needs replacing.
Every tyre has a date code stamped on the sidewall, usually four digits in a small oval. The first two digits are the week and the last two are the year. A code of 2421 means the tyre was made in the 24th week of 2021. Most manufacturers recommend replacing tyres at ten years, and some say six or seven for cars that sit outside in the sun.
If one side of the tyre is wearing faster than the other, or the centre is wearing before the edges, something is out. It can be tyre pressure, wheel alignment, or a worn suspension component. Uneven wear shortens the life of the tyre and tells you there is a problem that will eat the next set too if you do not fix it first.
Not all tyre damage means the tyre is done, but some of it does. Check the sidewalls and the tread for these:
Under-inflated tyres wear on the edges and run hot, which shortens their life and raises the risk of a blowout. Over-inflated tyres wear in the centre and give a harsh ride. Check the pressures once a month when the tyres are cold, and use the figure on the tyre placard, not the one moulded into the sidewall. The sidewall figure is the maximum, not the recommended pressure.
Front and rear tyres wear at different rates because they do different jobs. Rotating them, moving the fronts to the back and vice versa, evens out the wear across the set and extends the life of all four. We rotate tyres as part of a wheels and tyres service, usually at every service or every 10,000 kilometres.
If one tyre is damaged and the other three have plenty of tread, you can replace it alone. If two are worn on the same axle, replace both. Replacing all four at once is ideal because it keeps the handling balanced, but it is not always necessary. We will measure what is left on each tyre and tell you what makes sense for your car and your budget.
The right tyre for your car depends on the size, the load rating, and the speed rating stamped on the sidewall. The placard inside the door tells you the factory size and pressure. European cars often run specific load and speed ratings that you should match or exceed. We do not push one brand. We help you choose a tyre that suits the car, the way you drive, and your budget. You can read more on our wheels and tyres page.
If your car has a spare, check it when you check the other four. A space-saver spare has a speed limit, usually 80 km/h, and is meant to get you to a workshop, not to drive on for weeks. A full-size spare needs the same tread and pressure checks as the rest. If the spare is ten years old, it is past its use-by date even if it has never been used.
Not sure whether your tyres need replacing? Call 0481 797 861 or bring the car to our Moorabbin workshop and we will check the tread, the age and the pressures and tell you what is left.
Our Moorabbin workshop is open to talk through your service or repair and give you a quote before any work starts.
