Do You Know Your Tyre Tread Depth

Road  Safety Article

By Jonas Agwu

Gbemisola Richards, (not real name) is a female member of my Church. She drives a 2003 Honda CR-V. During my usual safety rounds on Sunday 26 February, 2023, my eagle eye spotted abnomalies on all her four tyres. As usual, I counselled her on the state of her four tyres.

The four tyres by my physical inspection were substandard. The tread depth was dangerously low. But like a typical road user, she was very ignorant of the risk and astonished at my submission. Her reaction was further heightened when she heard of how much the new tyre now cost.

Gbemi is the second road user from my Church in a space of two weeks who drives around ignorant of the dangers her tyres poses to her. Like I told you last week when I wrote on the first lady from my Church, this ignorance is not peculiar to our clime as even those in developed clime exhibit same. I therefore urge you to take time to regularly check the state of your tyres.

But while you may be considering changing some or all of your tyres, I wish to bring you up to speed on shady deals by some tyre dealers as shared by two of my friends when they went to Apo mechanic village in Abuja, the Federal Capital Territory to buy new tyres. I don’t know what the experience is in other parts of the country especially in places like Lagos, Onitsha, Kano among others.

Tim was the first to lament on what he called a new dimension by some dealers. “They have shown me pepper in that place. I bought four new tyres, and at the point of fixing it to the car, it was changed to re-grooved ones by the dealer! They bought me yam pepper soup to keep me away from their antics, not knowing that I will inspect the entire tyres before payment. This took my time, and I swore not to go to Apo again. Many of them are full of tricks.”

Shola equally shared his own experience, saying that “I’ve had the same experience before in Apo. Both the apprentice and Oga are criminals. Police need to set up an investigation into their activities.” This is why as a practice I only patronise known dealers to avoid being ripped by these fraudsters who care less about human life.

Let us now conclude on our focus on tyre tread depth. Like I told you last week, the legal limit of tyre tread is 1.6mm.The legal tyre tread is 1.6mm across the central three-quarters of the tyre, with the tread having to have this minimum requirement across its complete circumference. Like I told you last week, following new research findings in the United Kingdoms, experts have urged the Government to rethink the law to help protect drivers from facing danger on the roads.

Some of these experts submit that the current legal limit for tyre tread depth is too low and it’s putting millions of motorists at risk. What this means is that your tyre may meet the legal limit but may not be fine or safe. Yet a huge number of motorists whose tyres are dangerously low on tread assume that, if their tyres meet the legal requirements, they must be fine.

When I wrote about tyres in December 2022,I urged you to always  seek an expert  to conduct a careful examination of all areas of the tyre, inside and out, by a trained specialist. The removal of the tyre from the wheel is essential because internal damage is not visible while the tyre is fitted.

Before your tyres are worn down to the legal limit of wear like the case of Gbemi, it is a good idea to check your tyres regularly for tyre wear. But how? Here’s a simple way to tell if your tyres are worn out using a Michelin tyre. A Michelin man figure on the shoulder of a Michelin tyre shows the location of the tread wear indicators situated in each of the main grooves of the tread. These indicators are small raised areas at the bottom of the grooves of the tread pattern.

If the surface of the tread rubber is level with these raised areas, the tyre tread depth is most likely very close to the legal limit of 1.6 mm. Beyond this limit, you are putting your safety at risk and you are breaking the law. Even if the remaining tread depth is greater than 1.6 mm, you should adapt your speed and driving style to the external conditions, particularly on wet roads. Winter tread wear indicators at 4 mm (only in some European countries) The intermediary tread wear indicator indicates a remaining tread depth of 4 mm.

What if your tyre shows signs of aging: Tyres have no predictable life. It doesn’t matter when the tyres were made. Tyres age even when not used, or if only used occasionally. There are many factors that will affect the life of the tyre such as temperature, maintenance, conditions of storage and use, load, speed, pressure as well as driving style. These will have a great impact on the length of service life you can expect from your tyres. Pay regular attention to your tyres.

For these reasons, Michelin recommends that all drivers pay regular attention to the external appearance of their tyres for clear signs of aging or fatigue. This can include cracking of the rubber or deformation, etc. Excessive aging of tyres may lead to loss of grip. Michelin also recommends all tyres, including the spare, are inspected regularly by a tyre specialist. They can tell you whether your tyres should continue in service.

How old is too old? Your tyres should be thoroughly inspected at least once per year. If the need arises, follow the recommendations of the vehicle manufacturer regarding replacing the original equipment tyres. As a precaution, if the tyres have not been replaced 10 years from their date of manufacture (see how to read a tyre sidewall), Michelin recommends replacing them with new tyres. Even if they appear to be in usable condition and have not worn down to the tread wear indicator.

What if your tyre is damaged? Your tyre can be seriously damaged if it impacts any solid object on the road, like a kerb, pothole, or sharp object. Any visible perforation, cut or deformation must be checked thoroughly by a tyre professional. Only they can tell you whether the tyre can be repaired or has to be changed. Never use damaged tyres or tyres that have run flat or at very low pressures unless they have been thoroughly examined internally and externally by a tyre professional. Inspection by a professional is absolutely necessary because internal damage is not visible while the tyre is mounted; only then can a decision be made as to whether the tyre can be out back into service.

Remember I also guided you on what to do should you have a puncture reminding you that modern tyres are very sturdy and can cope with most things. Punctures, though, can and do still happen. A tyre specialist should check your tyre after a puncture to decide whether it can be repaired. Meanwhile, there are safety procedures to follow when you have a puncture while on the move: The first thing is to always consider your safety and that of your passengers; therefore you should pull off the road in a safe place. Put on the parking brake, switch off the engine and put the car in a low gear (or in Park on automatics) and switch on your hazard warning lights. Then you should wear a yellow high-visibility vest and place a warning triangle at the side of the road 100m behind the car. Your safety comes first – always!

Again I gave you helpful tips for changing a punctured wheel. First I warned you NOT to attempt to change a wheel if it risks the safety of you or your passengers. I advised you to always carry a pair of sturdy gloves and a bin bag in your boot, in case the tyre you’re removing is covered in mud! Carry a sturdy board to place your jack on in case the ground is soft, to avoid the jack sinking in. Where necessary, use light machine oil on the wheel nut threads to help their removal.

Check the inflation pressure of the spare tyre before fitting. If this is not possible, once fitted, drive carefully at low speed until it can be checked. Visit the nearest service station and inflate the tyre correctly. Badly tightened wheel nuts risk damage to the brake discs or wheel mounting system, use a torque wrench to make sure you tighten the nuts correctly with the correct torque.