Tread is the very bottom of a tyre that makes contact against the road surface.
Tyre tread is important because the rigid tread blocks make sure your tyres can grip the ground on both wet and dry surfaces and keep you moving safely. But tread isn't just about safety, it also affects how well you use fuel and how your tyres wear. If you've ever seen a car hydroplane when it gets caught in a puddle and the driver loses control, that's what happens when the tread isn't deep enough to hold on to the road. If the tread is too deep you'd be wasting fuel and wearing out your tyres far faster than they need to be.
Tyre's tread depth has been regulated for years by tyre standard bodies worldwide, coming up with standards based on the size of your tyres. On average, you should have at least 4mm of tread for any full-sized car tyre, while some high-speed performance sports cars will sometimes need no more than 2 or 3 millimetres of the tread to stay safe. For technical information, take a look at the Tyre and Rim Association of Australia website.The depth of your tread can be measured by taking a look at the tyre sidewalls and seeing how many millimetres your tread is below the crown line. Your tyre will also have easy-to-read signs on the side.
Both symmetrical and asymmetrical tyres with a tread depth below the minimum mandated by law are not legal for use on public roads. This could earn you demerit points. The use of bald tyres will compromise the performance of your vehicle during wet conditions. A lot of people don't realise how much tread depth and tread pattern affect their ability to steer and brake when they are driving, no matter what type of vehicle you are in. Checking tyre tread depth regularly can help save lives. Another thing to watch out for with low-tread tyres is road noise. If your car is making excessive noise coming down the road, it could be worth having your tyres checked by a mechanic or tyre centre because most likely they do not meet the minimum tread requirement needed.
Driving on tyres that have worn down past the legal minimum depth can have serious consequences when you are behind the wheel. They are not fuel-efficient and also you could have a major accident if you lose control of your car especially on a wet road.
Trying to drive on bald tyres can also damage the rim and sidewall of your tyre, making it seem as though you need to replace all four tyres at once.If you don't want to take any chances with road safety or vehicle wear and tear, make sure you check your tyre tread depth regularly and see what kind of shape they are in. If you're unsure, take them to a mechanic for assessment and be advised on the exact measurement that you need, for example, for dry handling and also ask them to recommend a reliable replacement.A spare tyre with the correct tread depth for your vehicle provides a temporary solution to get you back on the road should you get a flat or blowout. Driving unsafely with insufficient tyre tread is illegal and can result in fines and points on your license. It's important to keep track of how much tread your tyres have because it will affect the below,
Vehicle performance: If your car is harder to control, that could be due to low tyre tread depth. It's unsafe and you use more fuel.
The responsiveness of your steering wheel when cornering becomes dangerous if you don't have good grip under the front wheels.
Your braking ability. With less grip at the wheels, your braking distance increases.
The safety of your vehicle, passengers and others on the road: It's harder to react when you don't have enough grip.
Different types of tyre tread are available depending on the weather or road conditions you need to deal with. Some tyres have all-season tread designs for drivers who don't want snow chains or winter tyres, while others are designed with extra tread specifically for snowy, icy wet roads. If your car is a front-wheel drive, all-season tyres are meant to provide enough traction throughout the year without causing any damage to your vehicle. All-terrain jeep tyres are often more aggressive than typical SUV tyres and come in dedicated off-road designs that can navigate through sand, mud, rocks and other difficult terrain. Radial technology used on most modern cars gives them an advantage over earlier models when it comes to stopping safely even if they have minimal tread grooves. Directional tyre treads provide high protection in the case of aquaplaning and improves directional stability. They work specifically in one direction.
Any tyre with a tread depth below the minimum mandated by law is no longer legal for use on public roads. Your car's owner manual will indicate where you can find the sidewall of your tyres to check their various measurements, including the ones that tell you when they need replacement. In some cases, you'll find the number on the sidewall to clearly indicate where you should take a peek at your tyre tread. The numbers give a percentage of how much of the actual tyre surface is still covered by rubber treads. At least one of those measurements must be 1/16th or more in order for your tyres to meet legal standards. If your tyre is not uniformly worn out with one side still above the legal minimum and the other side below the minimum depth, it's still unroadworthy. If you're wondering how often you should check your tyre tread, the answer is right on your tyres: it's different for every manufacturer and every type of tyre. You can also use a tyre gauge to take the measurement. Inspect your tyres regularly to be on the safe side.
It can be hard to see exactly where the bottom of the tread grooves in your tyres stops and where the rubber begins, but make an effort to find out as soon as possible because you only have a few millimetres minimum legal tread depth. One way to know for sure is by checking them against the wear indicator bars embedded in each tyre, but this isn't always easy. If you don't have access to indicator bars, use a coin instead because its edge usually reaches the bottom of your tyre tread. If you can't make out any details or measurements on your tyres, visit a tyre store and ask for assistance before driving again because unsafe tyres are illegal and risky.
The minimum legal tyre tread depth in Australia is 1.5mm over any continuous length of 6.5cm.
Legal tyres must be clearly marked by tyre manufacturers with a pattern of wear bars on the inside of each groove which indicates acceptable wear levels.
Older tyres with worn-out tread patterns or less than 1.5mm thickness may not have enough grip when you need them most, especially in wet weather when hydroplaning can occur unexpectedly and lead to road accidents.
Driving on illegal tyres will also reduce the lifespan of your car's other components such as brakes, suspension and steering components because they have to work harder when there isn't enough grip from the tyres.This increased wear and tear may lead to more expensive repairs in the long run. Always have new tyres fitted to your car when the tread depth is too low. Also, ensure that that they are the right tyres for your car model.
The above information is not intended as legal advice. Check with your local requirements.