Your tyres are one of the most important parts of your vehicle when it comes to safety, handling and braking. But unlike regular servicing, there isn't one set time or mileage when every tyre needs to be replaced.

So, how do you know when it's time for new tyres?

The answer depends on several factors, including tread depth, tyre condition, age and how you drive. Here are some of the key signs to look for.

1. Check Your Tyre Tread Depth

Tread depth is one of the clearest indicators of tyre condition.

In New Zealand, the minimum legal tread depth for most car tyres is 1.5 mm around the tyre's principal grooves.

However, you don't necessarily need to wait until your tyres reach the legal minimum before replacing them. As the tread wears down, grip can be reduced, particularly on wet roads.

Checking your tread regularly can help you identify worn tyres before they become a safety concern.

2.Look for Cracks, Bulges or Damage

A tyre can need replacing even if it still has plenty of tread.

Check your tyres regularly for signs such as:

Cracks in the sidewall

Bulges or bubbles

Cuts or visible damage

Objects embedded in the tyre

Unusual or excessive wear

Some types of damage can affect the safety and reliability of a tyre. If you're unsure, have the tyre inspected by a professional.

3.Watch for Uneven Tyre Wear

Your tyres should wear relatively evenly.

If the inside, outside or one particular area of the tyre is wearing noticeably faster, there may be an underlying issue such as incorrect tyre pressure, wheel alignment or a suspension problem.

Replacing the tyre without addressing the cause could result in the new tyre wearing unevenly as well.

4. Don't Forget About Tyre Age

Even a tyre with plenty of tread can deteriorate as it gets older.

Rubber naturally ages over time, and factors such as sunlight, temperature, storage conditions and vehicle use can all affect its condition.

That's why tread depth shouldn't be the only thing you check. Older tyres showing cracking, hardening or other signs of deterioration should be professionally inspected.

5. Your Driving Habits Matter

How and where you drive can affect how quickly your tyres wear.

Your tyres may wear faster if you regularly:

Drive long distances

Travel on rough or gravel roads

Brake or accelerate heavily

Carry heavy loads

Drive with incorrect tyre pressure

Frequently encounter demanding road conditions

If you cover a lot of kilometres each year, it's a good idea to check your tyres more frequently.

6. Don't Just Wait for Your Next WoF

A Warrant of Fitness checks whether your vehicle meets minimum safety requirements at the time of inspection, but tyre condition can change between WoF inspections.

A tyre that passed its last WoF will continue to wear as you drive.

Checking your tyre tread, pressure and overall condition regularly can help you spot potential problems before your next inspection.

So, When Should You Replace Your Tyres?

There isn't one replacement interval that works for every vehicle.

You should consider replacing your tyres when:

The tread is approaching the legal minimum

You notice significant cracks, bulges or damage

The tyres are excessively or unevenly worn

They are showing signs of age or deterioration

A tyre professional recommends replacement

Rather than focusing only on kilometres or years, look at the overall condition of your tyres.

Final Thoughts

So, when should you replace your tyres?

The best time is when their condition starts to affect their safety and performance—not simply after a certain number of kilometres or years.

Regularly checking tread depth, tyre pressure, wear and visible damage can help you recognise when it's time for replacement.

Keeping your tyres in good condition is a simple but important part of safer driving on New Zealand roads.