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.
Every year in the U.S., tire-related crashes cause 200 fatalities, according to the National Highway Traffic Safety Administration. Thankfully, it’s easy to monitor your tires, and how to tell if you need new tires, with a quick video and some basic information.
The primary functions of the tread on your tires are to grip the road and to divert water that causes hydroplaning. Tires with plenty of tread can help you maintain control and reduce your chances of getting a flat.
With a quick monthly check of your tread and tire pressure, you’ll know if you need to replace your tires.
Tread wear bars are small, raised bits of rubber that run between the tread blocks. As these bars become even with the top of the tread, it is likely time for new tires. See more about tread wear bars below.
Tires will wear down over time, even if you don’t drive much. Sunlight, heat, and chemicals used to melt snow and ice can reduce rubber flexibility, causing tires to crack, lose air, and eventually fail.
There are many factors that may cause uneven wear, which could shorten the life of your tires. Vehicle alignment, tire pressure, lack of rotation, and/or worn steering and suspension components can all contribute to this problem. To prolong the life of your tires and reduce uneven wear, consider getting them rotated at consistent intervals. At Les Schwab, we recommend getting them rotated every 5,000 milles.
The pros at Les Schwab will also conduct a free visual inspection of your steering and suspension components. Schedule your free, pre-trip safety check today.
All tires deflate slowly over time, usually about 1 PSI (pounds per square inch) per month. Check yours monthly to keep them properly inflated. If your tires continually lose air or seem to completely deflate without warning, you may need to stop by Les Schwab for tire repair or replacement if necessary. Does the TPMS (Tire Pressure Monitoring System) light often appear on your dash? This could mean your tires have developed a slow, continuous leak.
If you hit a curb, pothole or other obstacle, your tires can develop sidewall bulges due to a break of the inner liner. These bulges can rupture causing a potentially unsafe situation. If you spot a bulge on your tires, get to your nearby Les Schwab and have your tires inspected.
If you experience new vibrations or thumping while driving, it could be a sign that one of your tire/wheel assemblies is out of balance.
It could also indicate a suspension issue. Stop by your local Les Schwab and our professionals will check your tires, steering, and suspension.
All tires sold in the United States today have what are called tread wear bars. The tread wear bars on your tires are there to help you see how much tread you still have. These wear bars are small, raised bars of rubber in the grooves of your tire. Look at the tread pattern and you’ll see these bars running between the tread blocks.
Look at the tread pattern and you’ll see these bars running between the tread blocks. As your tires wear, these bars will become increasingly flush with the tire’s tread. It’s important to replace your tires before this happens.
Depending on where and how you drive, and the conditions you face on the road, you might consider getting new tires before they reach that point.
City driving in mild conditions may allow you to wait until the tread is closer to the tread wear bar before replacing your tires. More adverse conditions, such as rain, snow, and unpaved roads, may require you to replace your tires earlier.
An easy way to check the tread on your tires is to do the penny test. Take a penny and place Lincoln’s head in one of the grooves of the tire tread. If you can see all of Lincoln’s head, it’s time to replace the tire.
If the penny goes in enough that the tire tread is at least as deep as Lincoln’s forehead, your tires are generally considered safe and do not need replacing. Check all four of your tires when conducting the penny test.
You’ll find your next set of tires at Les Schwab. You also find our world-class customer service at a tire shop near you that cares about your safety on the road.
SHOP TIRES
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.
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.
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.
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.
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.
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.
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.
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.
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.
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 |
| Winter with regular or asymmetric tread | 9 mm |
| High-speed winter | 7 mm |
| Summer tires with classic tread | 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.
If you have assessed the condition of your tires on all of the above factors and realized that the tires are worn out, be sure to replace them with new ones as soon as possible.
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03/20/2017
How to determine tire wear? At first glance, everything seems simpler than simple, it is necessary to divide the remaining tread height by the original height, however, the result of these actions will be erroneous. So how do you know when it's time to start thinking about buying new tires?
To find out the residual tread height, you need to measure both tires from the same axle and select the minimum tread height from the obtained ones.
According to the traffic rules, 2 mm is a critical mark, but it should be understood that this indicator can only be applied to summer tires, and even then not to all. Winter will lose its main characteristics already by 4 mm. Therefore, your real minimum tread will be in the range from 2 to 4 mm, depending on the type of tire, seasonality, as well as on your individual operating conditions.
For such a simple measurement, you will need any suitable device: for example, a caliper or a ruler with a depth gauge. You can also use an ordinary coin inserted into one of the grooves on the tire. If the tread hides only the rim of the coin, you need to change the tire, but if half the coin is hidden, then there is no point in thinking about buying a new one. However, with such a measurement, the accuracy of your measurements suffers, and you will not receive accurate data on the uniformity of wear.
The tire tread height must be measured at a minimum of 6 points. For example, in the center and on both edges of the tread, as well as at points around the circumference of the tire. Important: the measurement results at all points must match !
1. The tread is higher at the edges than at the center. This indicates that the tire has been inflated for a long time.
As a result of this use, the load on the power carcass of the tire has been increased. Driving on this tire is not recommended.
2. Tread higher in the center than at the edges means the tire has not been underinflated. If there are no obvious signs of driving on a completely flat tire (the pattern is erased from the upper part of the sidewalls), then you can still ride on such a tire, but even in this case, wear must be determined by the minimum tread height.
3. The tread is unevenly worn across the width (one of the edges of the tire is worn out). Such wear indicates a faulty vehicle suspension.
4. The tread is worn unevenly around the wheel circumference (the central or side blocks have different heights at different points on the circumference). Such wear indicates the "extreme" preferences of the owner. The tire has most likely seen extreme braking and/or acceleration. This tire can be safely scrapped.
5. Erased pattern (pattern) in the upper part of the sidewall of the tire (junction with the tread area - the rubber is “chewed”).
