Even the best of tyres wear out and eventually need to be replaced. How fast that happens depends on a multitude of factors such as the types of roads you usually drive, your driving style or tyre storage conditions. What also affects a tyre lifespan is undoubtedly the quality of the tyre itself - its construction and design.

Close up of man’s hands changing a car tyre

So, when should you change your car tyres? There are four major criteria that you should think of when taking a decision to swap out old, worn tyres:

While the last criteria is simply a matter of taste or plan to give your car a sharper look, the other ones are definitely connected with specific tyre characteristics, and they may need to indicate a need to replace the tyres earlier than expected. In this article we will focus on the age and tread wear factors.

How often should tyres be replaced?

In the UK (as well as most of Europe) the legal tread depth for summer tyres is 1.6mm. This is the minimum length between the height of the wear bars and the level of the tread wear index (TWI).

The thickenings in the grooves on the tyre perimeter are called “wear indicators.” They are found on the borderline between the tread and the side of the tyre.

An example of a wear indicator on Michelin tyres

A wear indicator in the form of a triangle

If a tyre reaches such a wear level, it should be replaced immediately -  its further use is illegal. In the case of a roadside inspection, the driver can be fined and the police may even retain the vehicle registration certificate. 

In the case of a car accident, your car insurance claim is very likely to be denied regardless of whether or not you caused the accident. And with the tread worn down to the TWI, road accidents are more likely. 

Numerous tests and studies have shown that a tread depth of 3-4 mm adversely affects the tyre’s performance on wet roads, especially when a strong resistance to aquaplaning is concerned. This only gets worse when the tread is wearing down to 1.6mm.

How many miles can you drive on summer tyres?

This depends how much you drive every year. With an average mileage of around 30,000 miles a year, tyres may need to be replaced on a yearly basis. However, how many miles a tyre will ultimately lasts depends on a large range of factors, including:

  • The wear resistance of the tyre including the compound, tread pattern and structure
  • Your driving habits
  • The types of routes (such as city, motorway or rural roads) that you take.
  • The types of surfaces you usually drive on
  • The tyre pressure level
  • The load index and weight of your car
  • Your driving speed

A tyre used to the TWI level.

The list is actually much longer, and that’s why it will always be difficult to talk about average values of wear resistance. However, an analysis of wear resistance shows that they are characterized by normal distribution. The largest number of drivers, operating in a moderate manner, reach a range of 15,000 to 30,000 miles with their tyres.

How often should winter tyres be replaced?

The compounds used in winter tyres are usually characterised by a lower wear resistance than summer variants. As a result, the mileage from a winter model can often be 15-30% shorter than traditional summer tyres. This distance can be shortened even further if such tyres are used at temperatures higher than 10 degrees Celsius.

How often should all season tyres be replaced?

When it comes to all season tyres, these should be treated similarly to winter tyres, as far as the tread depth is concerned. This is especially important when you consider that, in the majority of multi-seasonal tyres, the winter properties are lower than those found in dedicated winter tyres.

As far as durability is concerned, all season tyres sit somewhere between summer and winter options. In addition to being more suited for summer driving, they will often show their advantage over winter tyres during autumn and spring. From an economical point of view, it is unwise to use winter tyres outside of winter as they wear excessively then.

However, this is specifically relevant for all season tyres designed for the European market. Alternatives designed for American markets, or even cheap models provided by Chinese tyre companies, are sometimes characterised with an above-average wear resistance. Yet, it should be noted that this is achieved at the expense of their safety parameters and these tyres rarely comply with European road requirements.

Tyre age criterion

Regarding the age criterion, it is often said that tyres should not be used for longer than 10 years after the manufacturing date, even if the tread depth is in line with legal regulations and the tyre bears no visible signs of ageing.

Does this mean that you can’t use tyres older t-han 10 years? You can, but they are definitely less safe. With time, the tread compound, as well as other components of the tyre construction, lose their properties. Also, the tyre is more susceptible to various kinds of damage and failure due to its progressive corrosion processes and many years’ wear and tear.

If a tyre has a 3-digit marking on the manufacturing date, we should think about replacing them. Additionally, it is often recommended to have the tyres inspected regularly by a specialist after their 5th year of use. 

As far as winter tyres are concerned, due to their increased wear, you should consider changing the tyres on your car when they are 5 years past their manufacturing date.

Tyres are also subject to ageing when they are not in use. This usually happens when:

  • Tyres are installed on a car which is not in use or on a car which is parked for a long time. They are becoming deformed and ragged.
  • The tyres are not correctly stored in appropriate conditions. You always need to store car wheels and tyres properly to make sure they keep their good properties for the next season. 

When you know, approximately, how long your tyres will last, you can make better decisions in terms of tyre value, wear resistance and general use. Regular checks, sensible use and maintenance can maximise the lifespan of your tyres.