Safety on the road is the number one priority for most car drivers, everyone wants to get home safely. No matter what car you drive, the condition of your tyres is more influential in the safety of your car and the way it grips the road than almost anything else. It doesn’t matter how many safety features your car is loaded with, if there’s no grip left on your tyres they don’t mean anything. Are you looking to purchase a used car and want to check how much distance you will get out of the tyres? Or do you need to replace your current car tyres and are looking at affordable used tyre options? Either way, it’s good to know all about tread depth, what is acceptable and what is not.
First, let’s start by looking at the main causes of tyre wear
Tyres will wear over time just by general use of the vehicle, however there are a couple of things that can lead to premature tyre wear:
- Improper inflation. If the tyre is under or overinflated then it’s not able to do the job it was designed to do properly, leading to the tyre wearing unevenly.
- Incorrect air pressure. Check the air pressure in your car’s tyres at least once a month with an air pressure gauge, and don’t forget to check the spare too. The manufacturer’s air pressure specifications are usually on a placard on the inside edge of the driver’s door or along a door jamb.
- Improper wheel alignment. This may also lead to your tyres wearing unevenly and prematurely. If your car’s wheels are out of alignment, you should be able to feel a slight tugging through the steering wheel.
What’s the legal minimum tread depth?
The average tyre has around 8mm of tread depth when brand new. When tread depth gets down to 3mm, it is recommended you replace your tyres and at the minimum tread depth of 1.5mm, the tyres are considered worn out and must be replaced. Failing to do so and continuing to drive on tyres with this tread depth or below will severely compromise safety and may endanger your life and the lives of those on the road around you. It may also lead to hefty fines and even demerit points. So when purchasing used tyres, it’s imperative you check the tread depth – if it is at 3mm or below steer clear!
Other things to look out for when buying used tyres
We have discussed the importance of tread depth, but what else can you check when looking at used tyres?
- Exposed Cords: Look carefully at the tread surface all around. Irregular wear can expose the braided steel cords inside the tyre. If you can see the cords, or even a few thin steel wires coming out of the tread, the tyre is dangerous.
- Improper Repairs: Make sure you look for punctures in the tyre, but also look inside and out for punctures that have been repaired. A proper repair is a full patch on the inside of the tyre. Definitely avoid large punctures or repaired punctures located within a few centimetres of either sidewall.
- Linear Damage. Signs of damage at the liner of the tyre, such as a stripe of wear around the sidewall that appears softer or has the presence of rubber dust, indicate that the tyre is unsafe for driving.
AME Automotive is a major supplier of new & used tyres in Perth and we ensure only quality used tyres are made available for sale to our customers. Our friendly and experienced staff can provide professional advice to ensure that you select the right tyres for your vehicle and budget so don’t wait, visit our Canning Vale store today.
You can make a pretty good argument that tyres are the most important part
of a car. Of course, the engine is essential to actually drive the car
and your brakes are the most important safety feature. But
your tyres are the only part of the car that actually touches the road. Without them,
there’s really no car at all and if they’re in bad shape they
will negatively affect the performance of every other system in your vehicle.
Brakes, handling and steering are just some things that are affected by bald tyres or misaligned wheels. Fuel efficiency will also be affected and tyres that are in poor condition are also more likely to fail at high speeds.
So, it is very important not only to look after your tyres but to know when they need to be replaced or at least assessed by a professional. Here are 10 warning signs that your tyres need attention or replacement from AME Automotive’s expert team of mechanics in Canning Vale, Perth.
1. Tread Carefully with Worn Tread
If someone offered you a free pair of gorgeous leather shoes with comfortable inner soles but with no grip at all, you’d probably turn them down. Because even though all those other things are great, the shoes aren’t much good if you’ll slip over all the time.
Tyre tread is much the same. It doesn’t matter if your tyres are top of the line and your car is luxurious. If the tyres don’t have enough tread, the car won’t be safe, especially in wet conditions. Tyre tread creates space for water to be funnelled away, thereby increasing the wheels’ effective contact patch. This increases traction, reduces stopping time and lowers the risk of aquaplaning. In fact, in Australia, there is a legal requirement that your tyres have at least 1.5mm of tread and penalties apply if your fail to comply.
Why ‘Just Enough’ Is Not Enough
In fact, you should consider new tyres before that 1.5mm minimum, because by the time your tyres are that worn your stopping distance in wet conditions will have increased by almost 20 metres. A study measuring the Volkswagen Golf V’s stopping time travelling at 80 km/h in wet conditions with premium Bridgestone tyres found that:
- With 8mm of tread, it took 53.6 metres to stop
- At 5mm that increased to 55.2 metres
- With 3mm tread, 59.6 metres were required to stop
- Once the tread got to 1.6mm stopping distance shot up to 70 metres
Check Your Tread Regularly
Most modern tyres feature built-in tread wear indicators that allow you to do a quick visual inspection of your tyres. There will be tread wear indicator bars running perpendicular to the direction of the tread. These are hidden at first but start to appear as the tread gets low. If you can see one or more of these starting to appear, use a tread depth indicator to double check. If the tread is 1.5mm or lower you need new tyres. If you drive regularly in wet conditions, it’s a good idea to make the cut-off point 2 or 3mm instead.
2. Cracked Sidewalls
Tyre tread is a major concern, but cracks in the sidewall of your tyres are no less of a problem. Over time, exposure to UV breaks down the oils and chemicals that keep the rubber in your tyre strong and flexible, leading to a tyre that is brittle like an old rubber band.
One of the first signs that this is happening will be the appearance of cracks in the tyres’ sidewalls – everything from hairline cracks to distinct valleys in the rubber. These cracks can lead to leaks but they can also result in sidewall collapse or the tread separating from the rest of the wheel. Both of these outcomes are catastrophically bad news for you as a driver, especially if they happen on the highway, in heavy traffic or both.
3. Bulges and Blisters Are Bad Business
Another bad sign for your tyres is blister-like bulges appearing on the surface. These are usually caused in one of two ways:
- Uneven weakening of a tyre’s outer surface can lead to bulges because the pressure inside the tyre pushes out the weakened area. This is similar to an aneurysm in a blood vessel – an aneurysm can blow out an artery and one of these could blow out your tyre.
- The rigid internal frame of the tyre may have been damaged, allowing air pressure to reach the more flexible outer layers of the tyre. This damage is usually caused by driving mistakes such as hitting potholes, mounting kerbs, or driving with low tyre pressure.
These bulges will significantly reduce a tyre’s structural integrity and each additional bulge only makes the problem worse. Even if your tyres look fine otherwise and have plenty of tread, you need to get them replaced. Continuing to drive on bulging tyres is a recipe for a gradual flat tyre at best and sudden tyre failure at worst.
4. Bad Vibrations
It’s inevitable that you will feel some vibration when you drive, simply due to the engine doing its work and the friction of your car against the road. But if your notice more than usual, you probably have a problem. Excessive vibration usually comes down to one of four causes:
- One or more of the wheels could be bent or damaged, causing them to spin in an imperfect circle.
- The tyre may have suffered internal damage leading to irregular spinning, despite the wheel being okay.
- Poor wheel alignment will lead to vibrations and cause tyres to wear unevenly.
- A variety of suspension problems can also lead to a lot of vibration.
If your tyres or wheels are damaged, you will most likely need to get them replaced. If the cause is alignment issues or problems with suspension, those problems will need to be fixed.
5. What’s That Noise?
You can gather valuable clues about the health of your vehicle’s engine, brakes, tyres and more from the sounds your car makes. When tyres produce strange noises such as whining, squeaking, or thumping, think of it like a pet trying to tell you they’re ill. It’s not easy to know exactly what the problem is, so you’ll need to get a professional involved, but strange sounds from your tyres always indicate a problem.
It could be that the tyre or wheel has become damaged from a bump or simply through the stresses of daily driving. The wheels could also be out of alignment, leading to strange sounds when braking or cornering. Squeaking or thumping sounds could also be early indications that the tread on your tyre has worn down too low.
6. You Can’t Teach an Old Tyre New Tricks
Tyres have an age limit after which they should be retired. The maximum service life for car tyres is generally agreed to be around a decade, but that’s an absolute maximum – you generally don’t want to leave tyres on your car for 10 years.
Most manufacturers and suppliers only provide a maximum of five years’ warranty. After that time, the rubber’s natural deterioration – caused by UV radiation, friction, heat, and oxidisation – make problems increasingly more likely. As such, it’s usually recommended that you replace your tyres every five to six years, even if they look okay in other ways. If you insist on keeping older tyres, make 10 years your absolute cut-off point; after that, you’re asking for trouble.
Find Your Tyre’s Birthday
It’s actually quite easy to work out the age of your tyres. On the sidewall of every tyre is a 10-11 digit Tyre Identification Number (TIN). This tells you a lot of information about the tyre including its week and year of manufacture. For tyres from the 1990s, the last three digits give this information, and for post-2000 tyres, it’s the last four digits. So, for example:
- If the last three digits of your tyre are ‘278’ (with a triangular indentation next to them), then your tyre was manufactured in the 27th week of the year 1998. That means it celebrated its 10-year anniversary in 2008. Replace it as soon as possible.
- If the last four digits read 1315, then your tyre was manufactured in week 13 of 2015. They won’t need to be replaced until 2020-21 and will be officially past their used by date in 2025.
- If your tyres have a three digit code at the end of their NIT, but there is no triangular indentation next to it, then your tyres come from the 1980s. Frankly, it’s a miracle they haven’t exploded or split in half – replace them today.
What about the Spare?
While spare tyres are under less stress and strain in your boot, the rubber will still deteriorate. Spare tyres that are older than six years should only be used in an emergency and spares ten years or older should be replaced.
7. Uneven Tread Wear
If the tread on your tyres is wearing down unevenly, this could mean a lot of things. If the wear is severe enough you’ll need new tyres even if the rest of the tread is fine – all it takes is one or two bald patches to cause problems in wet weather or during a sudden stop. There are a few reasons why your tyres might be wearing unevenly:
- If the tyres are more worn on the outer or inner edge, the problem is probably misaligned wheels. If your wheels are angled in at the front, there will be more wear on the outer edges; if they point outwards there will be more wear on the inner edge.
- Tyres that show a lot of wear straight down the centre are a sign that you’ve been overinflating your tyre.
- If your tyres are worn at the edges, but not in the centre, you have been under inflating them. Get out of this habit right now – underinflated tyres don’t absorb bumps properly. They also result in more friction with the road, increasing the heat in your tyres and the chance of a blowout.
8. Tyre Landscapes
If your tyres have a ‘hill and valley’ pattern of wear – known as ‘cupping’ – they may need to be replaced. Your suspension will also need a check-up. Worn or damaged suspension can cause tyres to bounce as you’re driving, coming down harder on some parts of the tyre than others.
9. Feathering and Heel Toe-ing
Sometimes an incorrect toe setting on your car’s wheels can cause your tyres to spin in odd ways, creating an effect called ‘feathering’. This can also be caused by suspension problems.
Feathering is when your tread blocks end up shaped like ramps running sideways across your tyres. You’ll need to organise an alignment, suspension and have your tyres checked. If the wear is significant enough, you will also need new tyres.
Heel Toe Tyres
Heel-toe wear in tyres looks very similar to feathering, but it runs front to back along the tyres, not across them. If you find this wear profile on your tyres, get your car checked out – it could be the result of insufficient wheel rotations, misaligned wheels, damaged or worn suspension bushings, ball joints, or wheel bearings.
10. Dry Rot Is as Bad as It Sounds
Pervasive dry rot is a sign your tyres are no longer useable. If you’ve been checking for sidewall cracks and bulges, your tyres shouldn’t ever get to this stage, but if you’ve been negligent in examining your tyres, check them right now. If you find the following symptoms, drive very carefully and slowly to your nearest tyre service centre and get your tyres replaced.
- Do you have pervasive cracks in both the sidewall and the tread?
- Has the rubber turned from black to a dull grey?
- Can you see fabric or metal through the cracks in your tyres?
If you answered yes to any of these questions, you probably have dry rot. Your tyres are in a state of advanced decay. The rubber has lost most of its structural integrity and your tyres have become brittle and weak. Your tyres are now likely to fall apart, burst, or tear away from their steel belt any day now.
Contact AME Automotive mechanics in Canning Vale, Perth to get your car tyres checked if you’re experiencing any of these problems or before a long drive.