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When should you replace the tyres on your car?

Published 12 May 2017

Tyres are one of the most overlooked aspects of car maintenance and Government data shows that more than one in 10 cars will fail its annual MoT due to defective or worn out tyres. 

However, with a few basic checks and a little bit of knowledge, it is easy to keep on top of tyre maintenance and ensure they're safe and legal. 

Tread depth

The first and most obvious aspect of tyre safety is tread depth. And by this we mean the deepness of the main grooves that cover the circumference of the tyre. From new, the depth of tread will be around 7mm, while the legal limit is 1.6mm.

Most tyres have tread wear indicators, which are hard, raised bars at the bottom of each groove. When the tread is level with these bars then the tyre will have reached the legal limit. However, it is unwise to rely on these alone as uneven tyre wear is a common problem.

Poor wheel alignment or worn suspension can produce uneven wear to the inside or outer edge of the tyre, while leaving the tread bar intact.  To check the condition, run a 20p coin along the tread - the outer edge of the coin is 1.6mm thick and if the tread is below this mark then it will most likely be below the legal limit. 

Should you run a tyre to the legal limit?

As mentioned, the legal limit for tread depth is 1.6mm and - until recently - all tyre manufacturers, suppliers and motoring groups recommended tyre replacement at 3mm. However, owing to developments in tyre compound technology, some manufacturers are beginning to dismiss this advice. 

Michelin, for example, claims that its tyres are designed to provide as-new performance all the way to the 1.6mm limit. The French tyre maker is also campaigning for EU tyre ratings to be changed to reflect worn performance for all tyres at 1.6mm.

Whether you replace at 1.6mm, 2mm or 3mm is down to personal preference and the quality of the tyre that's fitted to the vehicle. But it's important to note that tyres that are near or on the legal limit can be more susceptible to aquaplaning, owing to the fact there is less tread depth to allow for water dispersion. For example, a tyre with 1.6mm of tread will not perform as well as one with 3mm when confronted with a road that may have 2mm of water on its surface.  

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Damage

As well as becoming worn, tyres are susceptible to damage. Unlike a puncture or excessive wear, damage can be difficult to spot, with no immediate impact to the car's handling. It can also occur from something minor, such as simply driving over a pothole, but the ramifications can be extremely serious.

Blisters, bulges or splits in the sidewall are usual indicator of serious internal tyre damage. Sunlight can also cause cracks, although this is usually found with cars that are left standing outside for long periods. However, it's important to check your tyres once a week as damage can result in a loss of pressure or a sudden blowout. 

Run flats

Run flat are self-supporting tyres that are designed to work even after a puncture. Run flat tyres are also less susceptible to blowouts, due to their reinforced sidewalls that hold the tyre up after damage or loss of pressure. That said, they're not indestructible and need to be regularly inspected for tread and condition. Unlike standard tyres, run flats cannot be repaired, which means they have to be replaced if they're damaged. 

How long should a tyre last?

How long a tyre lasts will very much depend on your driving style and type of vehicle. According to Michelin, an average tyre should last 25,000 miles. However, if you don't use your car very much - or own a classic - then tyre manufacturers' recommend that all tyres regardless of depth should be replaced after 10 years. We'd recommend having all tyres inspected annually if they're older than five years. 

Tyre pressure 

Underinflated or overinflated tyres can increase wear and affect the handling of your car. You’ll find the correct pressures for your car’s tyres in the owner’s manual or inside the fuel filler flap. They will be stated in ‘Bar’ or ‘PSI’, so make sure you use the same figures for every tyre. Always try to use the same pressure gauge so you know the readings are consistent across all four corners when you check them once a week.

Using a pump or compressor, you can add air to any tyre that is under-inflated. Add a little at a time and check with the gauge until the tyre is at the right level. Avoid over-inflating and then letting air out through the valve as this puts unnecessary strain on the tyre. 

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Comments

MrPogle    on 13 May 2017

So some tyre manufacturers claim that you get as-new performance at 1.6mm and tyres at the legal limit are more prone to aqua planing.

They can't both be true.

HighlanderUK    on 13 May 2017

hmm, never seen tyre pressures listed inside a fuel filler cap before, must be small text.

usually its on the inside of the driver door B pillar, beside the door catch.

sixcylinder    on 15 May 2017

hmm, never seen tyre pressures listed inside a fuel filler cap before, must be small text. usually its on the inside of the driver door B pillar, beside the door catch.


You need to go to Specsavers, it said "inside the fuel filler flap" not the cap.

anne hall    on 16 May 2017

With our ( UK ), constantly wet weather and increasingIy heavier downpours, I consider it safer to change my tyres, regardless of manufacturer, at 3 mm not only for standing water which may be deeper than the minimum 1.6 mm 'Legal Minimum Limit' but also unknown integrety of the compound as well as variable and unseen stresses, strains and impact damage during their lifetime.

Also, as previously mentioned, inflation figures can sometimes be found on the fuel filler flap and, as I discovered on a holiday hire car recently in Tenerife, so called 'Comfort Pressures' as an option to 'Standard'.

Over the past two years, I have discovered that a premium Scandanavian-made 'All Weather' tyre is proving to be the optimum choice for all types of vehicles both in very cold and hot British weather, with unbeatable grip in all conditions especially rain, snow and even ice, and absolutely no difference in braking efficiencey between seasons ! Well worth the extra tenner a corner in my opinion.

"Stay Safe !"

( NHS District Nurse )

Edited by anne hall on 16/05/2017 at 11:12

paul sainsbury    on 14 May 2017

Mine are listed on the inside of the filler cap, I have a Mercedes. I think BMW's have the info on the door pillar.

gramar    on 14 May 2017

I have a SEAT Altea XL, tyre pressures are listed inside the fuel flap whereas on my wife's Suzuki Ignis they are on the drivers door pillar.

conman    on 17 May 2017

I have no problem with changing my tyres earlier, but the tread depths should be increased to 9/10 mm. therefore tyres last longer, are safer, cause less pollution and save us all money, a no brainer.

anogginthenog    7 days ago

'Run-flats cannot be repaired' - not true. Some manufacturers say they can. Then repairers have their own ideas, often mistaken. See www.etyres.co.uk/run-flat-tyres/repairing-run-flat.../

Edited by anogginthenog on 19/05/2017 at 18:06

k night    5 days ago

Where is the manufacture date on the tyre? I have bought Toyo Proxies which had side wall cracks after 2 years (on a SMART).

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