There’s no fixed mileage that tells you it’s time. Some tyres are worn out at 30,000 km, others still look fine at 60,000. It depends on the tyre, the car, the roads and the driver. What really decides it is how much tread is left, what condition the rubber is in, and how old the tyre is.
Here’s how to judge all three.
01Tread depth
A new car tyre usually starts with around 7 to 8 mm of tread. The legal minimum in most countries is 1.6 mm, and every tyre has small raised bars across the bottom of the main grooves, called tread wear indicators, set at that height. When the surface of the tread is level with those bars, the tyre is finished.
The bars can be hard to spot. On many tyres a small triangle or the letters TWI on the shoulder show where they sit, and there are usually six of them spaced around the tyre.
In practice, don’t wait that long. Below about 3 mm, braking on a wet road gets noticeably worse, and the first rain of the season here catches out plenty of drivers on tyres that looked fine in the dry. A tread depth gauge costs very little and gives you a real number instead of a guess.
02What uneven wear is telling you
Look across the whole width of the tread, not just the middle:
- Both outer edges worn: the tyre has been running underinflated.
- Centre worn more than the edges: too much pressure.
- One edge worn, usually the inside: the wheel alignment is out. More on that in alignment vs balancing.
- Patchy, cupped or scalloped wear: often worn shock absorbers or a wheel that’s out of balance.
Fix the cause before fitting new tyres, or the new set will go the same way.
Feel the tread as well as looking at it. Run your hand across the tyre in both directions; if it feels smooth one way and rough or saw-toothed the other, that’s early uneven wear, often from alignment.
03Damage that means replace, not repair
A small puncture in the main tread area, up to about 6 mm, can usually be repaired properly with a plug-patch fitted from the inside. Some damage can’t be fixed safely:
- Any puncture or cut in the sidewall or the shoulder.
- A bulge or bubble on the sidewall. That means the internal structure is damaged. Replace it straight away.
- Cuts deep enough to show the cords underneath.
- A normal tyre that’s been driven any real distance while flat. The sidewall gets crushed from the inside even if it looks fine. Run-flats are a separate case, covered in run-flat tyres explained.
04Age
Rubber hardens and cracks with time, and heat speeds that up. A tyre with good tread can still be too old to trust. Check the four-digit DOT date on the sidewall; our guide to reading the DOT date code shows you where to find it. Past five or six years in this climate, look at your tyres closely, whatever the tread says.
05Two tyres or four?
If only two need replacing, put the new pair on the rear axle, even on a front-wheel-drive car. It sounds backwards, but grip at the back is what keeps the car from spinning if you have to swerve or brake hard on a slippery road.
On all-wheel-drive cars, including many SUVs, Teslas and Audi quattro models, a big difference in tread depth between front and rear can strain the drivetrain. Check what the maker recommends. Often the answer is all four at once.
Worn or damaged tyres are also one of the common reasons cars fail the annual vehicle test at registration renewal, so it’s worth checking before your test date, not after.
Rotating your tyres every 8,000 to 10,000 km helps all four wear at the same rate, so they reach the end together and you can replace them as a set. It also means someone looks at each tyre regularly, which is how small problems get caught early.
06Next step
When it’s time, find your size in the finder or start with a popular one like 205/55 R16 or 235/45 R18. Every tyre shows its manufacturing year and the fitted price, with fitting, balancing and nitrogen included. Not sure which size you need? Here’s how to read it.