When should you change all four tyres on a car?

You don’t always need to replace all four tyres on your car at once. Here’s how to tell when a complete set is needed, when two tyres will do, and what to check first.

Your tyres are the only parts of your car that are in contact with the road, so keeping them in good condition is essential for safe driving.

But do you really need to change all four at once?

Not necessarily. If only two tyres are worn, replacing them as a pair may be enough. However, there are situations where fitting four new tyres is the safer or more appropriate choice.

This handy guide walks you through when it’s time for a complete set.

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When should you change all four tyres?

You should consider replacing all four tyres when:

• All four tyres are approaching the end of their useful life, which is typically between seven and 10 years.
• They have similar levels of wear and are close to the legal minimum tread depth of 1.6mm or the recommended replacement point of 3.0mm.
• The tyres are old, cracked or otherwise showing signs of deterioration.
• You want to replace a mixture of different tyre types, brands or tread patterns with a consistent set.
• Remember that tyre condition isn’t just about tread depth. Age, damage, wear patterns and your vehicle’s requirements all need to be considered.

How worn do tyres have to be before you replace them?

In the UK, car tyres must have at least 1.6mm of tread across the central three-quarters of the tyre and around its entire circumference. Going below this is illegal.

However, you don’t want to wait until your tyres reach the legal limit.

National Highways recommends changing tyres before they get this low, suggesting 2mm in summer and 3mm in winter as good practice. Deeper tread can be particularly useful in wet conditions because it helps the tyre clear water from the road.

If all four tyres are approaching the end of their useful tread at around the same time, replacing the complete set can make sense.

It’s worth checking your tread regularly rather than waiting for your MOT, particularly before a long journey. Check it at several points across each tyre rather than relying on a single measurement.

Check the whole tyre, not just the tread

Tread depth is only part of the picture. Look for:

• Cracks or splits in the rubber
• Bulges or other sidewall damage
• Cuts or punctures
• Uneven wear across the tread
• Excessive wear on one edge

Uneven wear can indicate problems with wheel alignment, suspension or tyre pressures. Any underlying issue should be addressed before fitting new tyres.

If you notice unusual wear or damage during a routine check, don’t wait until the tyre reaches the legal tread limit before getting it assessed.

Do you have to change all four tyres on a 4×4 or AWD car?

Not always – but check the manufacturer’s instructions before replacing fewer than four.

4×4 and AWD systems can be sensitive to differences in tyre circumference. Significant differences between tyres can affect the drivetrain and, on some vehicles, potentially damage components such as the differential or gearbox.

Some manufacturers require all four tyres to be replaced together, while others allow a specific difference in tread depth.

Check your owner’s manual or ask a tyre specialist before mixing tyres on an AWD or 4×4 vehicle. The requirements vary between cars.

What about tyre age?

Tyres deteriorate with age, even if they haven’t covered many miles.

Rubber becomes less resilient over time, particularly after prolonged exposure to sunlight and the elements.

Tyre manufacturer Michelin recommends having tyres professionally checked at least annually once they have been in use for five years, and recommends replacing them 10 years from their date of manufacture as a precaution.

You can find the manufacturing date in the tyre’s DOT/TIN code. The final four digits show the week and year of manufacture.

For example, a code ending in 2322 means the tyre was manufactured in the 23rd week of 2022.

If several tyres are reaching the end of their recommended service life at around the same time, replacing the complete set may be appropriate.

Can you replace just one tyre?

Sometimes, but replacing one tyre requires more care.

If one tyre is damaged but its partner on the same axle is significantly worn, fitting just one new tyre could create a substantial difference in tread depth.

A single tyre replacement is more likely to be suitable when the other tyres are relatively new and the replacement tyre matches the others.

The replacement should meet the manufacturer’s requirements for size, load index and speed rating, and should be the same as the tyre on the opposite side of the axle.

If you have a puncture, check whether the tyre can be safely repaired before buying a replacement. Some punctures in the main tread area can be repaired, while damage to the shoulder or sidewall will generally require a new tyre.

Do all four tyres need to match?

Ideally, your tyres should be appropriately matched to give the car consistent grip and handling.

This includes matching:

• Size
• Type and construction
• Load rating
• Speed rating
• Tread pattern
• Season or compound

However, some cars are designed with different-sized tyres at the front and rear. Always follow the vehicle manufacturer’s specification rather than assuming all four tyres should be identical.

It’s also worth checking your tyre pressures regularly. Use the pressures recommended by your vehicle manufacturer and check them when the tyres are cold. Correct pressures help maintain grip, handling and tyre life.

What about winter and all-season tyres?

If you’re changing from summer tyres to winter tyres, it’s generally recommended to fit the appropriate tyres to all four wheels, rather than putting winter tyres on just one axle.

Mixing summer and winter tyres can give the front and rear of the car different levels of grip and handling.

If you use all-season tyres, make sure they meet your vehicle manufacturer’s specifications and are suitable for the conditions in which you drive.

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