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.
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Tires
When your tire treads wear thin, you could be in for a slippery ride—literally. Luckily, you can spot dangerous tread depth using only a penny, and Honest Abe’s face! The penny test is quick, easy, and can help you know exactly when to replace tires.
To check your tread depth, you don’t need any fancy tools or expert knowledge.
Grab a penny, and you have everything you need!
For reference, the distance between the top of a penny and Abe’s head is about 2/32nd of an inch. If you can see the top of his head, your tread is less than 2/32nd of an inch and your safety may be at risk. Depending on where you live, continuing to drive on such thin tread could actually be against the law.
"Most states require a minimum of 2/32 of an inch (approximately 1.6 mm) of tread, but two require less, some have no requirements, and some defer to the federal criterion for commercial vehicle safety inspections," reports the National Center for Biotechnology Information.
With adequate tire tread depth, your car is able to grip the road. This is especially important when roads are snowy or wet, or when you’re driving on less-than-ideal surfaces. Once tread becomes shallow, your tires are more prone to slipping and sliding, creating a dangerous situation for yourself and other drivers on the road.
When your tires are worn, other components of your vehicle can begin to wear prematurely, too, as your vehicle experiences excess strain. While new tires can be a big investment, they’re an investment worth making.
Reach into your pocket and pull out your spare change. Give the penny test a try—it only takes a few minutes—and find out if it's the right time to replace your tires. If you're short on change, just find your nearest Firestone Complete Auto Care. Our stores offer free tire inspections that include tire tread depth measurement!
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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.
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.
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.
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.
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.
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%.
| Statistics say that a third of car drivers do not know how to determine the degree of tire wear and the need to replace them. Also, not all car drivers know what is the minimum tread depth allowed by our legislation. The legislation of Latvia determines that the minimum allowable tread depth for summer tires is 1.6 mm , and, in turn, for z winter tires - 4 mm. Compared to other European countries, Latvia leads the way in this requirement. in other regions of Europe, the requirements require a minimum tread depth of 3 mm. Many factors contribute to tire wear, one of which is driving style . For fans of aggressive driving, tires wear out faster because they warm up faster and begin to wear out. In addition, tire wear contributes to improper tire pressure, too much weight load and chassis defects . Therefore, it is necessary to regularly check the condition of the tires, because from the point of view of safety and handling, they are the most important part of the car. Every driver should carry out a visual inspection of tires at least once a month, since each tire has wear indicators, most often located in the water channels. First of all, it is necessary to assess the degree of wear of the tread. This can be done in several ways, such as using a digital tread gauge.
New tire B/U But the easiest way to determine whether the depths of the minimum scheme were reached, it was a check of the depth of the protrusion using double coins.
New tire Used tire
In addition to visual inspection, it is necessary to check the tire pressure, because the correct pressure affects not only their wear rate, safety, fuel economy and driving comfort, but also car parts. Tire pressure can be checked at any gas station, as well as in tire centers, where specialists will carry out the necessary checks, including visual inspection. At the same time, the service is free of charge and, for example, in Pirelli Key Point tire centers throughout Latvia, time for it does not need to be reserved in advance. However, PKP recommends not relying solely on indicator wear and definitely not waiting until the tread has reached the minimum permitted depth (1.  |
It should be emphasized that usually the tread depth of new tires is 6-8 mm for summer tires and 8-10 mm for winter tires. 
The outer part of the ring-shaped coin, made of nickel and copper, is 2 mm wide. By placing a coin in the drainage channels, you can approximately measure the tread depth. You can also use the tread depth gauge provided by Pirelli Key Point. 
