How to check tread on winter tires


How to check your tread and other tips before the snow starts falling – The Denver Post

By Tom Krishner, The Associated Press

It’s time to get some traction.

At any time now, snow could fall over a broad swath of America, and that means your tires need to be checked.

Experts say if the rubber is worn, you could slide, crash or get stuck, even in a light snowfall. Depending on where you live and how badly you need to get someplace in bad weather, you might want winter tires. All-season tires might be an option, but they won’t start and stop as well in ice and snow.

Experts say late October is a good time to shop for tires and get them installed so you’re ready. Here’s how to figure out whether you need new tires and tips from experts on what kind of rubber to buy:

Check the tread depth: Stick a quarter into the tire grooves at several spots with George Washington’s head upside down. If you can see the top of Washington’s hair, you have 4/32 of an inch of tread or less. That means it’s about time to replace your tires. You may have a little time left in warm, dry weather, but tires with less than 4/32 won’t grip well in ice and snow. People used to use a penny to check tread depth. But if the top of Abraham Lincoln’s head can be seen, that means you’ve only got 2/32 inches of tread left. “At that point most tires are basically worn out and need to be replaced immediately,” says Gene Petersen, tire program manager for Consumer Reports, which does extensive tire testing.

Winter or all-season? It depends on where you live, how urgently you need to be somewhere in the snow, and whether your vehicle is 2-wheel-drive or all-wheel-drive. In an area with moderate snowfall, you probably can get by with all-season tires, especially if you can wait for plows to clear roads before going anywhere. Generally, if you live south of Cincinnati, Ohio, then all-season tires should work, says Woody Rogers, director of tire information for Tire Rack, an online tire store in South Bend, Ind. But to the north, where heavy snowfall is more likely, winter tires will be better. If the engine powers all four of your wheels, good all-season tires may suffice. Generally, winter tires on a two-wheel-drive vehicle grip better than all-season tires on a four-wheel-drive vehicle. Experts say all-wheel-drive makes a big difference starting off in snow. But it won’t help you stop in snow. That’s where winter tires come in. They’ll stop faster in slippery conditions because they grip ice and snow better due to specially designed soft tread compounds. In bad weather, winter tires grip almost like they’re being driven on dry roads, says John DiPiazza, part owner of A&A Tires in Milwaukee. “It’s quite amazing,” he says.

Read the reviews: If you decide to go with all-season tires, make sure you read test reports and consumer ratings. All-season tires vary wildly in their ability to grip snow, says Rogers, whose store also does tire testing. “The gap from good to bad is staggering,” he says. DiPiazza says you should stick to well-known brands for the best performance. If you choose winter tires, also read reviews. Tire Rack’s tests show less of a variance between snow tires from different brands. Deeper grooves generally mean more snow traction, but you can’t always tell performance from looking at a tire, Petersen says. Although winter tires have improved, they still compromise dry-pavement handling for snow and ice performance.

Replace all four tires: Putting snow tires on just the two drive wheels can make your car difficult to handle in snow and ice. When two wheels on one axle grip better than the other two, it creates a handling imbalance that could be treacherous if you’re trying to stop quickly or steer around something. “Those are the situations where you need your car to work best, an emergency situation,” says Rogers.

The price: Snow and all-season tires generally cost about the same. Consumer Reports found that sedan tires average around $145 each. SUV tires average $178 apiece. Shopping around could get you a better deal. Make sure the price includes mounting and balancing.

Buy early: Experts say now is the time to buy, when there’s time to do research and there’s an abundant selection of snow or all-season tires. If you wait until the first snowfall, you might get stuck with what the dealer has on hand in the size that fits your car. But don’t buy too soon: DiPiazza recommends installing winter tires when the daily high temperature is generally below 50 degrees.



Join the Conversation

We invite you to use our commenting platform to engage in insightful conversations about issues in our community. We reserve the right at all times to remove any information or materials that are unlawful, threatening, abusive, libelous, defamatory, obscene, vulgar, pornographic, profane, indecent or otherwise objectionable to us, and to disclose any information necessary to satisfy the law, regulation, or government request. We might permanently block any user who abuses these conditions. As of June 15, 2022, comments on DenverPost.com are powered by Viafoura, and you may need to log in again to begin commenting. Read more about our new commenting system here. If you need help or are having issues with your commenting account, please email us at [email protected].

Most Popular

  • Club Q shooting suspect is nonbinary, defense attorneys say

    Club Q shooting suspect is nonbinary, defense attorneys say

  • Editorial: We’re looking at you, Lauren Boebert. Stop the intolerance.

    Editorial: We're looking at you, Lauren Boebert. Stop the intolerance.

  • The 7 best barbecue joints in Denver, in the opinion of a Kansas City native

    The 7 best barbecue joints in Denver, in the opinion of a Kansas City native

  • Club Q shooting suspect ordered held without bond in first court appearance

    Club Q shooting suspect ordered held without bond in first court appearance

  • Utah woman awarded nearly $2.

    4M after Vail Resorts employee hits her with bowling ball

    Utah woman awarded nearly $2.4M after Vail Resorts employee hits her with bowling ball

  • Keeler: Why couldn’t Broncos great Ed McCaffrey cut it as UNC football coach? “No system. No organizational skills.”

    Keeler: Why couldn't Broncos great Ed McCaffrey cut it as UNC football coach? "No system. No organizational skills."

  • Club Q shooting suspect changed name in 2016 to protect themself from birth father, court records show

    Club Q shooting suspect changed name in 2016 to protect themself from birth father, court records show

  • The Club Q shooting suspect identifies as nonbinary. Will that affect potential hate crime charges?

    The Club Q shooting suspect identifies as nonbinary. Will that affect potential hate crime charges?

  • What we know about Anderson Lee Aldrich, the alleged Colorado Springs Club Q shooter

    What we know about Anderson Lee Aldrich, the alleged Colorado Springs Club Q shooter

  • Kiszla: Condoleezza Rice, once a child deemed unworthy of sitting on Santa’s knee, now sits in owners’ box at Broncos games

    Kiszla: Condoleezza Rice, once a child deemed unworthy of sitting on Santa's knee, now sits in owners' box at Broncos games

How to Check Tire Tread Depth: The Penny Test

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.

THE PENNY TEST

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.

    OTHER WAYS TO CHECK TIRE TREAD

    TREAD DEPTH GAUGE

    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.

    TREAD WEAR INDICATOR BARS

    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.

    DON'T WAIT UNTIL IT'S TOO LATE

    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.

    How to determine the wear of summer 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.

    Tire wear index

    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:

    • grip with 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).

    3 ways to determine tire wear

    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.

    Uneven tire wear: how to determine the causes, what is dangerous

    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:


    How to assess tire wear visually: additional parameters

    • 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.

    How to calculate tire wear percentage

    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 high 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.

    How to determine winter tire wear

    Before the next winter, motorists who have driven for several seasons on studded or friction tires have a question. Should I buy new ones or old ones are still able to provide reliable grip on snow and ice? To make the right decision, you need to know how to determine the wear of winter tires, and what is its maximum allowable limit.

    Basic assessment parameters

    The main indicator of the suitability of tires for operation is the tread height. However, in the case of studded tires, the number of studs is an equally important factor. Even when there are almost none left, some motorists are in no hurry to get a new thing. Such drivers mistakenly think that in this way their tires have become frictional.

    But tires, which are popularly called Velcro, have a completely different rubber compound. They are much softer than studded ones and lose their valuable properties faster in the cold.

    Winter tire wear is estimated according to the following indicators:

    • residual tread depth;
    • presence/absence of hernias or other mechanical damage;
    • number of spikes.


    Permissible wear of winter tires

    The "List of malfunctions and conditions under which the operation of vehicles is prohibited" establishes a critical tread wear of a winter tire - 0.4 cm. But most manufacturers of studded and friction tires recommend changing earlier. To measure the tread height, a regular ruler will do. If the result is 0.5 cm, it is better to purchase new tires.

    It is necessary to measure the tread height not in one place, but in several, since wear can be uneven. For example, 0.6 cm may remain on one side of the tire, and 0.4 cm on the other. In this case, it is necessary to change the tires. You can buy winter tires at the TopDetal.


    Learn more