When it comes to checking tire tread, there are a number of methods that can help you know if it’s time to replace a tire. Heavily worn tread will prevent a tire from performing as designed and can lead to unsafe driving conditions. One of the simplest, most common ways to check tread depth requires nothing more than a penny and a few moments of your time.
In the United States, tire tread depth is measured in 32nds of an inch. New tires typically come with 10/32” or 11/32” tread depths, and some truck, SUV and winter tires may have deeper tread depths than other models. The U.S. Department of Transportation recommends replacing tires when they reach 2/32”, and many states legally require tires to be replaced at this depth.
The idea of the penny test is to check whether you’ve hit the 2/32” threshold. Here’s how it works:
Place a penny between the tread ribs on your tire. A “rib” refers to the raised portion of tread that spans the circumference of your tire. Tire tread is composed of several ribs.
Turn the penny so that Lincoln’s head points down into the tread.
See if the top of his head disappears between the ribs. If it does, your tread is still above 2/32” , If you can see his entire head, it may be time to replace the tire because your tread is no longer deep enough.
When performing the penny tire test, remember not only to check each tire, but to check various places around each tire. Pay special attention to areas that look the most worn. Even if parts of your tread are deeper than 2/32”, you should still replace the tire when any areas fail the penny test.
Consistent wear around the whole tire is normal, but uneven tread wear could be a sign of improper inflation, wheel misalignment, or a variety of other things. If you see uneven tread wear, you should have a technician inspect your vehicle.
A simple way to check your tire tread depth is by using a tread depth gauge.
You can find tire tread depth gauges at your local auto parts store. There are many models available, but an inexpensive simple graduated probe gauge will work just fine. All you have to do is stick the probe into a groove in the tread and press the shoulders of the probe flat against the tread block and read the result. All gauges should measure in both 32nds of an inch and millimeters.
Another indicator of worn out tread already lives in your tires themselves. Every performance, light truck, or medium commercial tire comes equipped with indicator bars (or wear bars) embedded between the tread ribs at 2/32”. They’re there to help you monitor tread depth and make decisions about tire replacement. Just look to see if the tread is flush with the indicator bars. If they are, it’s time to replace the tire.
While the penny tire test does deliver on what it promises – indicating whether tread has reached the legal limit – it may not be the best indicator of whether your tires are safe for the road.
Tire performance can diminish significantly before your tread hits 2/32”. Even though the law deems fit for safe driving may not prevent you from hydroplaning or losing control in rainy, slushy conditions. If you think your tires may be close to needing replacement, have them checked out by a licensed mechanic.
If you are like most people, you only get concerned about tire tread depth when you notice that your tires are not gripping the road like they used to, or when you take your vehicle in for service and are told your tires need replacing.
However, the reality is that knowing what your tire tread depth in millimetres (mm) is – and knowing how to measure tire tread depth – is important information to know as a driver. Tire tread depth can affect your driving and your safety on the road very quickly, as a tire with worn out tread won’t give you the traction you might need in certain driving conditions, such as wet or snowy roads.
You may be wondering how to check the tire tread on your vehicle. Luckily, measuring tire tread depth is relatively easy and there are a couple of ways to do so. One easy way involves using a coin, such as a Canadian dime or quarter. Another is with a tire tread depth gauge. Below, we explain these two methods in better detail.
For real accuracy in checking tread wear, you may want to check the depth with a tire tread gauge. The latter are easily found at all your local hardware stores and online, and the ones that are sold for home use are relatively inexpensive.
When checking with a tread depth gauge, simply ensure your vehicle is parked securely, and then take the gauge and insert it into the grooves (cutouts) on the tread of your tire. When the head of the gauge touches the inside of the tread, you can then read the tire gauge (just like a tire pressure gauge) and see what your tread depth is in mm (millimetres). Any tread depth over 6 mm means your tires are safe and you can continue using them.
If you tire tread depth is 4/32”, then it is time to start looking for a new set of tires. And, if your tire tread depth is 2/32” or less, then you are actually driving in a highly dangerous condition and should seek to purchase a new set of tires immediately. A tread depth of 2/32” or lower can significantly impact your ability to stop safely in wet or snowy conditions, and is considered to be very unsafe.
One of the simplest ways to quickly check tire tread in Canada is by using a coin, such as a dime (10 cent coin). So, go head and dig into that coin jar, or under the couch cushions and look for a dime or a quarter.
Again, ensure that your vehicle is parked safely and securely first. Then, take a dime and turn it so that the Queen’s head is facing towards the ground – no disrespect to the Queen – and insert the coin into your tire tread groove. If the Queen’s head – including her crown – are fully visible to your eye, then it is time to replace your tires – ASAP.
If you see less of the Queen, then it is likely your tread depth is 4/32” or higher, meaning you should keep your eyes on your tires, but that you are likely safe enough to continue driving.
If you don’t have a dime handy, you can also use a Canadian quarter to check tire tread depth in Canada. Following the same rules as checking with a dime, when you insert your quarter into the tread with the Caribou’s head facing down. If you can still see the Caribou’s nose, you are starting to experience a lower tread depth and should start looking for a new set of tires.
It is best to check each of your four tires, just to be completely safe, especially if you have replaced single tires over the years and are driving with a mismatched set, or tires from different brands. Tires all wear quite differently, and the average tire tread life can vary between different brands and types, so it is possible that one or two tires have less tread depth than others. Or, you may have purchased a used car that has different tire brands installed on it, and so it’s good to develop a baseline for each tire in terms of tread depth.
Based on recommendations you should measure your tire tread every month. Of course, once you have determined that you have 4/32” or less tread depth on your tire, then you should check more frequently, but based on ensuring the safety of yourself, your family and of course other drivers on the road, you should be looking to replace your tires.
It is also a good practice to check tire tread depth before the winter season, because you want to make sure that you have at least 6/32” of tread depth to tackle winter road conditions. If your tires don’t meet this minimum requirement, then you may want to think about purchasing a set of winter tires for your vehicle.
At the end of the day, the main reason to be concerned about the available tread depth on your tires is safety. Tires with low tread do not grip the road as well as newer tires, and with a low tire tread you could experience:
For the sake of safety for both yourself and your family, it is important to regularly check your tire tread depth. Then, if you have determined that you need to replace your tires, you can start shopping.
One of the best ways to shop for a new set of tires to replace those with low tread depth is by looking online at a tire seller such as blackcircles.ca. Of course, if you have questions regarding tire tread depth and whether it’s a good time to replace the current tires on your vehicle, then you can reach out to the team at blackcircles Canada, and we will be happy to help you.
learn more about the safety of your tires
Tire wear in the United States is checked using a coin with the image of the first president of the country. A one-dollar coin is inserted into the groove of the tread with Washington's head down.
If Washington's hair is visible, then it's time to buy new tires. A coin with a face value of 1 cent will also help to check the wear of automobile rubber. If the top of the Lincoln is visible, then the tires have reached the tire wear rate and must be replaced immediately.
Tire wear can also be determined with a 1 euro coin. It must be inserted into that part of the tire where the tread is most worn. If the golden circle is in rubber, then the tire will still serve you. If the gold part of the coin is completely visible, then it's time to change the shoes of your car. nine0004
Tire wear can also be determined using Russian money. The domestic 2-ruble coin must be inserted into the protector with the eagle's head down. If the top of the bird is visible above the surface of the tire, then the tire has not yet reached the end of its life.
Premature tire wear can be avoided. According to the Research Institute of the Tire Industry (NIIShP), the "life" of half of the tires is reduced due to improper operation.
After all, the service life of rubber largely depends on driving style, road conditions, compliance with the load index and correct tire pressure. Therefore, it is not surprising that with the same model of car and “shoes”, the mileage of their tires can differ by several thousand kilometers. nine0003
The main causes affecting premature tire wear
For new tires, the break-in process is important. The first 200-300 kilometers of newly purchased tires should be extremely careful, especially in winter or in rainy weather. This is due to the fact that before vulcanization, the treads of new tires are covered with a separating layer, which should be erased only during operation.
Therefore, all types of rubber must be run-in. nine0004
Tire wear occurs in a variety of ways:
Uneven tire wear is normal because the tire is subjected to uneven loads while driving.
In this case, a new wheel balancing will help. In most cases, when sawtooth teeth form on the transverse grooves of the profile, it is necessary to use cruciform wheel balancing. But this will only help with the correct geometry of the axis. This will change the direction of the tire. The sawtooth teeth will gradually disappear, along with them the noise will also disappear. nine0004
If the wheels with asymmetric tread pattern are changed regularly, every 10,000 km, uneven wear of all tires can be avoided. But the replacement must be done on one side. That is, the front right wheel should only change to the rear right, and vice versa.
In 1992, a uniform wear rate for summer tires was established in Europe - the minimum profile depth for tires for cars, trucks and motorcycles is 1.6 mm. This requirement also applies in Russia. An exception to the rule are light wheels with a minimum tread height of 1 mm. But for wide-profile and summer tires, this rate is too small.
With such a profile depth on a wet road, the tire will have poor handling. For safety reasons, summer tires should be changed already when the remaining profile depth reaches 2 mm (wide profile - 3 mm). Modern winter tires have a tread depth of 9, depending on the manufacturer.-12 mm. Permissible wear for them is 4-6 mm.
Many modern tires have built-in wear indicators in the form of small rubber pimples. They are soldered into the base of the protector. When the tire wears down to acceptable limits, the pimples become flush with the tread. This means it's time to change the tire.
In addition, the American tire marking uses the TWI (Tread Wear Indication) tread wear indicator. Sometimes it is indicated by arrows. The tire wear indicator is located evenly in 6-8 places around the perimeter of the tire. nine0003
Over time, the life of the tire decreases, and at the same time, the percentage of wear increases. If the bead is damaged during installation, the percentage of wear increases to 10%.
Chipping, chips, cracks on the tread increase wear by 25%. 100% wear is assigned to a tire with carcass delamination.
The percentage of aging is added to the technical wear percentage. For 3 years of operation, the tire loses up to 10% of its resource. When using a tire for more than 5 years, the percentage of wear can reach 50%. nine0004
In fact, the average life of any tire is 5-7 years, but a lot depends on how the owner treats his car. Aggressive driving, improper seasonal tire storage, unrepaired suspension/balancing problems, incorrect pressure and other errors can significantly shorten tire life. But worn tires can be a serious problem on the road: an increased risk of uncontrolled skidding, hydroplaning, even accidents is the price that drivers and passengers have to pay for using old tires. nine0004
Each manufacturer indicates the so-called wear index on the tire profile, which most often looks like the inscription “Treadwear 100” and means a maximum of 48,000 km on a standard road surface (polygon).
In a real environment and often not the most ideal roads, this number actually needs to be divided by 1.5 - we get 36,000 km.
By analogy, if the wear resistance index is 150, then this means “factory” 72 thousand km, 200 - 96 thousand km., and so on.
What are the dangers of worn tires on the road:
adhesion to the roadway deteriorates, which leads to an increased likelihood of skidding, accidents, hydroplaning in case of rainy weather;
reduced cross-country ability in off-road conditions;
increases the risk of a tire puncture while driving. nine0004
It is also worth remembering that the issue of tire wear is regulated by traffic rules, and you can get a fine for using “bald” rubber. Knowing what maximum tire wear is acceptable, this is easy to avoid: 1.5-2 mm for summer, and 4-5 mm for winter (a more accurate figure is indicated by the manufacturer).
1.
According to the wear indicator on the tire. To find this indicator, you need to inspect the side of the tire and find one of the markings: a triangle, a company logo, a snowflake, or the abbreviation TWI. If the tread has worn down to this indicator, it means that the tire needs to be disposed of urgently. nine0004
2. Many people in the old fashioned way prefer to use a 10-kopeck coin. Insert it into the tread with the inscription "10 kopecks" towards you, and if it is visible, the wear level is too high, you need to replace the tire. This method is convenient, but not entirely accurate: by measuring wear in different parts of the tire in this way, it will be difficult to estimate its unevenness by eye, and this is also an extremely important indicator.
3. It is optimal to use a special gauge, depth ruler or caliper for these purposes. This will allow you to measure the wear of the tread in different parts of the tire with an accuracy of up to a millimeter and understand if there is uneven wear.
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If measurements show different results in different parts of the tread, it is important to determine exactly how your tires wear in order to understand where and what the operating error is.
If the tread wears more on the sides and the center wears off less, this means that the tire pressure is insufficient and the contact patch with the road is not correct. This leads not only to poor vehicle stability, but also to increased fuel consumption. nine0004
If the tread is worn down the middle but the sidewalls are fine, then your tires are overinflated. Sometimes this is done intentionally in order to save fuel, but in this case, the tires will still have to be changed ahead of schedule.
There is also the possibility of increased wear on the inside or outside of the tread - this indicates an incorrect camber. A visual table with wear options and their causes:
Cracks on the sides of tires can indicate frequent off-road driving, improper storage, low-quality rubber or long service life, as well as incorrect tire pressure.
Bulges or "hernias" on the sides of the tires appear as a result of the side part hitting hard obstacles. Tires with such damage are not recommended. nine0004
Dents on the tread indicate insufficient depreciation and unadjusted camber. Having found such damage, it is necessary to drive the car to the service and make sure that the suspension is in good condition.
Individual wear spots on the tread indicate aggressive driving / braking, skidding with wheel locks, or prolonged parking of the car in one position. nine0004
Most often, this is required for the sale and purchase of used tires in order to orient the buyer in the degree of their wear. Many sellers give this figure at random, but this method has nothing to do with the actual assessment of the degree of tire wear. It is also important to understand that a conditional 50% wear for a summer tire is an acceptable value, while 50% wear of a winter tire tread is a sign that the tire cannot be used.
Therefore, it is important to know how to accurately determine the percentage of tire wear so as not to get into an unpleasant situation. nine0004
Many people divide the actual tread height by the height of the same, but new tire, and get a certain percentage of wear. This would be correct, if not for one BUT: we cannot physically erase the tread to zero, and the law prohibits the use of tires with a tread below the permitted values.
You can calculate actual tire wear by dividing the difference between the new tire height and the actual tire height by the difference between the new tire tread height and the minimum possible tread height for that tire, and then multiplying this number by 100. nine0004
If it is impossible to find out the height of the same, but with a new tire, use the average values of your tire type:
| Tire type | Average tread height at start of use |
| Winter tires with Scandinavian tread | 10 mm nine0004 |
| Winter with regular or asymmetric tread | 9 mm |
| High-speed winter | 7 mm |
| Summer tires with classic tread nine0161 | 8 mm |
| Summer speed | 7 mm |
You can check summer tires for wear a little less often than winter tires, since in summer the tread depth is not so important for patency.
